NEWARK, NJ - FEBRUARY 01: Sen. Cory Booker (D-NJ) (C) announces his presidential bid during a press conference on February 1, 2019 in Newark, New Jersey. Sen. Cory Booker launched his 2020 presidential campaign today, joining an already crowded field of hopefuls with his Senate colleagues. Booker is the second African-American entering the race, after Sen. Kamala Harris (D-CA). (Photo by Eduardo Munoz Alvarez/Getty Images)
PHOTO: Eduardo Munoz Alvarez/Getty Images North America/Getty Images
NEWARK, NJ - FEBRUARY 01: Sen. Cory Booker (D-NJ) (C) announces his presidential bid during a press conference on February 1, 2019 in Newark, New Jersey. Sen. Cory Booker launched his 2020 presidential campaign today, joining an already crowded field of hopefuls with his Senate colleagues. Booker is the second African-American entering the race, after Sen. Kamala Harris (D-CA). (Photo by Eduardo Munoz Alvarez/Getty Images)
Now playing
01:39
Cory Booker's path to becoming a 2020 candidate
WASHINGTON, DC - JANUARY 16:  Physician to U.S. President Donald Trump Dr. Ronny Jackson listens during the daily White House press briefing at the James Brady Press Briefing Room of the White House January 16, 2018 in Washington, DC. Dr. Jackson discussed the details of President TrumpÕs physical check-up from last week.  (Photo by Alex Wong/Getty Images)
PHOTO: Alex Wong/Getty Images
WASHINGTON, DC - JANUARY 16: Physician to U.S. President Donald Trump Dr. Ronny Jackson listens during the daily White House press briefing at the James Brady Press Briefing Room of the White House January 16, 2018 in Washington, DC. Dr. Jackson discussed the details of President TrumpÕs physical check-up from last week. (Photo by Alex Wong/Getty Images)
Now playing
03:14
DOD releases scathing review of former White House physician
PHOTO: CNN/Getty
Now playing
02:10
'Highly misleading at best': Dale reacts to Pence's op-ed
PHOTO: Gov. Cuomo's office
Now playing
03:35
Gov. Andrew Cuomo addresses women's allegations
Commanding General District of Columbia National Guard Major General William J. Walker testifies before the Senate Homeland Security and Governmental Affairs/Rules and Administration hearing to examine the January 6, 2021 attack on the US Capitol on Capitol Hill on March 3, 2021 in Washington, DC. (Photo by Greg Nash / POOL / AFP) (Photo by GREG NASH/POOL/AFP via Getty Images)
PHOTO: GREG NASH/POOL/AFP via Getty Images
Commanding General District of Columbia National Guard Major General William J. Walker testifies before the Senate Homeland Security and Governmental Affairs/Rules and Administration hearing to examine the January 6, 2021 attack on the US Capitol on Capitol Hill on March 3, 2021 in Washington, DC. (Photo by Greg Nash / POOL / AFP) (Photo by GREG NASH/POOL/AFP via Getty Images)
Now playing
03:01
DC National Guard commander: 'Unusual' Pentagon restrictions slowed response to Capitol riot
Supporters of President Donald Trump hold up their phones with messages referring to the QAnon conspiracy theory at a campaign rally at Las Vegas Convention Center on February 21, 2020 in Las Vegas, Nevada.
PHOTO: Mario Tama/Getty Images
Supporters of President Donald Trump hold up their phones with messages referring to the QAnon conspiracy theory at a campaign rally at Las Vegas Convention Center on February 21, 2020 in Las Vegas, Nevada.
Now playing
03:00
Hear why QAnon supporters believe Trump will be president on March 4th
FBI Director Christopher Wray testifies before the Senate Judiciary Committee on the January 6th insurrection, in the Hart Senate Office Building on Capitol Hill in Washington, DC on March 2, 2021. (Photo by MANDEL NGAN / POOL / AFP) (Photo by MANDEL NGAN/POOL/AFP via Getty Images)
PHOTO: MANDEL NGAN/POOL/AFP via Getty Images
FBI Director Christopher Wray testifies before the Senate Judiciary Committee on the January 6th insurrection, in the Hart Senate Office Building on Capitol Hill in Washington, DC on March 2, 2021. (Photo by MANDEL NGAN / POOL / AFP) (Photo by MANDEL NGAN/POOL/AFP via Getty Images)
Now playing
02:55
Watch FBI director debunk conspiracy theories pushed by Trump supporters
WASHINGTON, DC - FEBRUARY 10: Neera Tanden, nominee for Director of the Office of Management and Budget (OMB), testifies at her confirmation hearing before the Senate Budget Committee on February 10, 2021 at the U.S. Capitol in Washington, DC. Tanden helped found the Center for American Progress, a policy research and advocacy organization and has held senior advisory positions in Democratic politics since the Clinton administration. (Photo by Anna Moneymaker-Pool/Getty Images)
PHOTO: Anna Moneymaker-Pool/Getty Images
WASHINGTON, DC - FEBRUARY 10: Neera Tanden, nominee for Director of the Office of Management and Budget (OMB), testifies at her confirmation hearing before the Senate Budget Committee on February 10, 2021 at the U.S. Capitol in Washington, DC. Tanden helped found the Center for American Progress, a policy research and advocacy organization and has held senior advisory positions in Democratic politics since the Clinton administration. (Photo by Anna Moneymaker-Pool/Getty Images)
Now playing
01:33
Neera Tanden releases statement on pulling her nomination
PHOTO: KCAL/KCBS
Now playing
01:41
Multiple people killed in crash after SUV and semitruck collide
nigeria kidnapped schoolgirls released Busari pkg intl ldn vpx_00000423.png
nigeria kidnapped schoolgirls released Busari pkg intl ldn vpx_00000423.png
Now playing
02:09
Tears of joy and relief as 279 Nigerian schoolgirls return home
New satellite images taken by Maxar show that North Korea sometime in the past year built a structure that may be intended to obscure entrances to an underground facility where nuclear weapons or nuclear weapons components are stored.
PHOTO: Courtesy Maxar
New satellite images taken by Maxar show that North Korea sometime in the past year built a structure that may be intended to obscure entrances to an underground facility where nuclear weapons or nuclear weapons components are stored.
Now playing
01:47
See images US intelligence claims is a secret weapons site
NEW YORK, NY - JULY 23: New York Gov. Andrew Cuomo speaks during the daily media briefing at the Office of the Governor of the State of New York on July 23, 2020 in New York City. The Governor said the state liquor authority has suspended 27 bar and restaurant alcohol licenses for violations of social distancing rules as public officials try to keep the coronavirus outbreak under control. (Photo by Jeenah Moon/Getty Images)
PHOTO: Jeenah Moon/Getty Images
NEW YORK, NY - JULY 23: New York Gov. Andrew Cuomo speaks during the daily media briefing at the Office of the Governor of the State of New York on July 23, 2020 in New York City. The Governor said the state liquor authority has suspended 27 bar and restaurant alcohol licenses for violations of social distancing rules as public officials try to keep the coronavirus outbreak under control. (Photo by Jeenah Moon/Getty Images)
Now playing
02:29
NYT: Third woman comes forward against Gov. Andrew Cuomo
PHOTO: Courtesy Penguin Random House
Now playing
01:00
These 6 Dr. Seuss books won't be published anymore
John King Magic Wall 0301
PHOTO: CNN
John King Magic Wall 0301
Now playing
03:00
US coronavirus numbers coming down, but not enough
FILE - In this Jan. 29, 2011 file photo, Saudi journalist Jamal Khashoggi speaks on his cellphone at the World Economic Forum in Davos, Switzerland. Saud Al-Mojeb, Saudi Arabia's top prosecutor, is recommending the death penalty for five suspects charged with ordering and carrying out the killing of Saudi writer Jamal Khashoggi. Al-Mojeb told a press conference in Riyadh Thursday, Nov. 15, 2018,  that Khashoggi's killers had been planning the operation since September 29, three days before he was killed inside the kingdom's consulate in Istanbul. (AP Photo/Virginia Mayo, File)
PHOTO: Virginia Mayo/AP
FILE - In this Jan. 29, 2011 file photo, Saudi journalist Jamal Khashoggi speaks on his cellphone at the World Economic Forum in Davos, Switzerland. Saud Al-Mojeb, Saudi Arabia's top prosecutor, is recommending the death penalty for five suspects charged with ordering and carrying out the killing of Saudi writer Jamal Khashoggi. Al-Mojeb told a press conference in Riyadh Thursday, Nov. 15, 2018, that Khashoggi's killers had been planning the operation since September 29, three days before he was killed inside the kingdom's consulate in Istanbul. (AP Photo/Virginia Mayo, File)
Now playing
02:52
3 names mysteriously removed from Khashoggi Intel report
Protesters take cover behind homemade shields as tear gas is fired during a demonstration against the military coup in Yangon on March 1, 2021. (Photo by STR / AFP) (Photo by STR/AFP via Getty Images)
PHOTO: STR/AFP/AFP via Getty Images
Protesters take cover behind homemade shields as tear gas is fired during a demonstration against the military coup in Yangon on March 1, 2021. (Photo by STR / AFP) (Photo by STR/AFP via Getty Images)
Now playing
02:16
Footage shows tear gas, flash bangs used on protesters in Myanmar
New York Gov. Andrew Cuomo speaks during a news conference at a COVID-19 vaccination site in the Brooklyn borough of New York, Monday, Feb. 22, 2021. (AP Photo/Seth Wenig, Pool)
PHOTO: Seth Wenig/Pool/AP
New York Gov. Andrew Cuomo speaks during a news conference at a COVID-19 vaccination site in the Brooklyn borough of New York, Monday, Feb. 22, 2021. (AP Photo/Seth Wenig, Pool)
Now playing
01:12
Gov. Andrew Cuomo responds to allegations of sexual harassment
(CNN) —  

New Jersey Sen. Cory Booker went public Friday with the least well-kept secret in politics: He’s running for president in 2020.

Booker joins a field already crowded with his Senate colleagues – Sens. Kamala Harris (California), Kirsten Gillibrand (New York) and Elizabeth Warren (Massachusetts) are already in or expected to be in soon – and with others like Sens. Amy Klobuchar (Minnesota) and Sherrod Brown (Ohio) also considering bids.

For Booker, his presidential bid is the culmination of a career – despite the fact that he is not yet 50 – that has long been on this trajectory. Since he emerged into the national spotlight as a crusading reformer taking on the established black power structure in Newark, New Jersey, in the early 2000s – if you have not watched the documentary “Street Fight” about his 2002 run for mayor, you must – through his election to the Senate in 2013, Booker has long carried the tag of “rising star who will run for president.” (Admittedly, that wouldn’t exactly fit on a name tag.)

And now, he’s running. He enters the race with real strengths – and some major questions surrounding him. Here are five things to think about Booker’s candidacy.

1. He’s the best, most natural speaker in the race

One of the ways to stand out in a very crowded presidential field is to have a skill no one else has. Booker has that in his emotional and charismatic speaking style. (If you need proof, watch his speech at the 2016 Democratic National Convention.) While Booker has – and will – face critics who hit him for his alleged theatrics, the truth is that Booker’s speaking ability will light up rooms in Iowa, New Hampshire and South Carolina. And likely help him stand out in debates while standing beside nine other 2020 politicians. He is also likely to benefit in the eyes of some Democratic base voters from the (overly facile) comparison to the last charismatic African-American speaker in national politics: Barack Obama.

2. He has a solid core of longtime aides around him

Because Booker has been seen as someone who will run for president since, basically, 2002, he’s attracted a large and talented group of senior aides who have been with him for years and who know him and his style well. Addisu Demissie, Booker’s presidential campaign manager, managed his 2013 Senate bid. Matt Klapper, a senior adviser to the campaign, has been Booker’s Senate chief of staff for years. Mo Butler was Booker’s chief of staff when he was mayor of Newark and will be a senior strategist on the presidential campaign. It’s hard to overestimate how important it is for a candidate running for national office to be surrounded by people a) who he trusts and b) who can say “no” to him. In the course of a two-year presidential campaign, you will say and do dumb things – or at least think dumb things. You need people who can stand up to you and tell you not to say and do those things.

3. He’s a tireless campaigner

Running for president is an absolute grind. You have to wake up a lot of mornings in some nondescript hotel room in Iowa or New Hampshire, with the thermometer hovering in the single digits and snow falling and spend the next 18 hours acting as though every person you meet is the single greatest person you have ever met. That’s very, very difficult. But Booker’s 2018 schedule – in which he campaigned like crazy for candidates all over the country – suggests he has the energy to do it and the understanding of what it takes. Plus, at 49, he will be nearly three decades younger than some of the other candidates in the race, which should help him manage the grind a bit better.

4. He’s largely unproven as a candidate

Booker has never really faced a deep dive into his background from a well-funded opponent. And his 2013 special election victory to the Senate raised some questions about whether he could stand up to that sort of scrutiny. There was the odd direct messages on Twitter with a stripper from Oregon that were never fully explained. And the mysterious figure of “T-Bone,” a drug dealer who Booker said once threatened to kill him. The problem was that when reporters went looking for T-Bone, no one could find him. And although Booker had repeatedly spoken of the man as though he was a real-live person, it appears as though there is no actual T-Bone. ‘“He is an archetype of so many people that are out there,” Booker said in 2007. “He is 1,000% a real person.” Which, like, still leaves things cloudy. Is T-Bone a real person? Or an archetype? Booker doesn’t lose a presidential race based on this question. But it does suggest he has some work to do on his back story. And fast.

5. His record isn’t perfect for liberals

Since coming to the Senate in 2013, Booker has cut a largely liberal figure. According to vote ratings by GovTrack, Booker is the 17th most liberal senator in the chamber. But in his past, he has dabbled in areas that could be problematic for liberals shopping for a candidate. Booker was a prominent advocate of school choice during his time as mayor of Newark – so much so that the city’s teachers union opposed his reelection in 2010. He worked with now-Education Secretary Betsy DeVos on school choice issues, although he did vote against her confirmation to her current role. And there there is the fact that earlier in his career, Booker was one of the top recipients of campaign donations from Wall Street. While Booker has since sworn off corporate PAC donations, there is a long record of giving – from both individuals and PACs connected to corporations – in his past races that his opponents will likely feast on.

CORRECTION: This story has been updated to correct the year of Booker’s “archetype” quote.