Mark Wilson/Getty Images
Washington CNN —  

They would seem to have big advantages going into the 2016 presidential race – prominent jobs in Washington, access to major donors and the ability to influence the major national issues of the day.

But being a member of the Senate hardly paves a clear path to the White House. Only three presidents – Warren Harding, John F. Kennedy and Barack Obama – have moved directly from the Senate to the White House.

That’s not stopping senators from eyeing the prize at the other end of Pennsylvania Avenue. At least six members of the world’s most exclusive club are considering presidential campaigns that could buck history.

The benefits

The Senate is one of the most important bully pulpits in American politics – overshadowed, only, by the White House itself.

“The advantages are you have a podium, you have the Senate floor, you can say things and attract press attention,” said Iowa Sen. Tom Harkin, who unsuccessfully sought the Democratic presidential nomination in 1992. “You are just not coming out of nowhere. If you are lucky enough to have a committee that you chair you can promote certain things. So you do have some built in mechanisms which help you run for president.”

Look no further than Kentucky Sen. Rand Paul and Texas Sen. Ted Cruz as examples of first term legislators who have effectively used the chamber – in particular the Senate floor – to their political advantage.

READ: Rand Paul dives back into Ferguson debate

For Paul, it was March 2013, when he walked into the Senate to express concerns about the U.S. drone program and to try and block the nomination of John Brennan to head the CIA. Nearly 13 hours later, the Kentucky Republican relinquished control of the floor but not before he turned the nation’s attention towards the use of drones on U.S. soil. “Stand with Rand” quickly entered the political vernacular and spread into the mainstream. Political supporters printed t-shirts and campaign signs with this phrase that will likely be a rallying cry if Paul ultimately decides to run for president.

Seven months later, Cruz stole the national spotlight by helping to shut down the federal government for 16 days in protest of the Affordable Care Act. In the summer leading up to October 1 – the federal government’s new fiscal year – Cruz sought support from grassroots activists to pressure Congress to oppose funding Obamacare.

The week before the shutdown, he spoke for more than 21 hours straight from the Senate floor criticizing the health care law. Several days later, the federal government shut down, which angered many Republicans who complained that his actions were nothing more than a political stunt that could hurt other Republicans. But Cruz won praise from like-minded conservatives – key allies if he decides to seek the GOP presidential nomination.

READ: Ted Cruz floats Lieberman to replace Hagel

The political perks of being a senator are countless as the position can help a lawmaker establish a national profile, and make important connections with deep-pocketed donors, powerful titans of business, influential activists and world leaders – all critical elements of a presidential campaign.

“You have to understand you will be taking part of your responsibilities away, but also the fact that you are a United States senator opens a lot of doors,” said Arizona Sen. John McCain, the Republican presidential nominee in 2008.

These doors are often opened by fellow senators, who ask their colleagues to attend fundraising events here in Washington and around the country. The senator headlining the event is provided the opportunity to meet donors and activists that otherwise would be out of reach. The senator, who is being honored at the fundraiser, gets to pocket donations for re-election. This quid-pro-quo is part of the daily political business in Washington, and ambitious senators can use it to their advantage.

“Name another job in politics where you can freely travel the country, and meet with big donors and activists,” said Alex Vogel, who served as senior political strategist to Senate Majority Leader Bill Frist, R-Tennessee, and as general counsel for the National Republican Senatorial Committee.

The drawbacks

Still, for all of the political benefits a senator has due to the trappings of the office, there is plenty of baggage that comes along with it and often it is opened up during a presidential campaign.

This is not a new phenomenon.

British scholar and politician James Bryce 126 years ago identified the hurdles a Member of Congress faces in seeking the U.S. presidency in his book The American Commonwealth. Bryce, who became British ambassador to the U.S. in 1907, observed in a chapter titled: ‘Why Great Men Are Not Chosen Presidents,’ that a relatively unknown candidate is a safer choice than a known candidate with a public record.

“The famous man has probably attacked some leaders in his own party, has supplanted others, has expressed his dislike to the crotchet of some active section, has perhaps committed errors which are capable of being magnified into offences,” Bryce wrote. “No man stands long before the public and bears a part in great affairs without giving openings to censorious criticism. Fiercer far than the light which beats upon a throne is the light which beats upon a presidential candidate, searching out all the recesses of his past life.”

Then-New York Sen. Hillary Clinton faced this problem when she ran for the Democratic presidential nomination in 2008. There was little unknown about Clinton, who lived most of her adult life in public view including eight years as first lady, when she ran for president. But Clinton’s rivals for the Democratic nomination, including then-Illinois Sen. Barack Obama, turned to her Senate record and criticized her for voting in 2002 to authorize the Iraq War. The war was unpopular with the Democratic base, and since Obama wasn’t elected until 2004 he wasn’t forced to vote on it. During the 2008 campaign, Clinton refused to say her vote was a mistake – she has since publicly stated it was a mistake.

“I think running for president from the Senate is tough, because you are constantly taking votes,” said former Sen. John E. Sununu, R-New Hampshire. “A lot of them are tough votes on strange amendments that are not always easy to explain in a 30 second commercial.”

Explaining votes can be just as politically damaging as actually casting them. Then-Massachusetts Sen. John Kerry, the 2004 Democratic presidential nominee, tried to clarify why, as a senator, he supported and then opposed a massive package to fund operations in Afghanistan and Iraq.

“I actually did vote for the $87 billion before I voted against it,” Kerry said at the time.

His explanation fell flat.

President George W. Bush’s campaign seized on Kerry’s comments and turned it into a television commercial.

What Kerry was trying to say was that he supported the funding package initially with the condition it would be paid for by the repeal of the Bush tax cuts for the wealthy. It wasn’t and he voted against it.

Florida Sen. Marco Rubio, who is considering a bid for the Republican presidential nomination, has had his own legislative headache over the issue of illegal immigration. He was a key player in crafting legislation in 2013 that dealt with all aspects of the problem including putting in force a plan to legalize the estimated 11 million illegals already living in the U.S. as well as strengthening border security. Conservative activists howled over the legalization effort and the House opposed it. Rubio is now focusing his attention on securing the border.

CEO vs. legislator

Perhaps one of the biggest problems for a senator seeking the presidency is that the field of candidates will include at least one, if not more, governors also interested in moving into the White House. Governors make the argument that they are forced to address real world problems on a daily basis, while senators debate, debate and continue to debate major issues. The Senate, is known after all as the “world’s greatest deliberative body.”

Harkin said voters also see this distinction when they are sizing up candidates: CEOs vs. lawmakers.

“There is a real difference between legislators and governors and that is why governors have a much better chance at being elected president,” said Harkin. “I think in the public’s view they see a governor as a mini president. They run the executive branch and they look upon legislators differently. They really do. I think that is a real drawback to any senator running.”

Unlike previous years, the Republican or Democratic Senate leader is not looking at running for president. The last two to seriously consider it were Frist and Senate Democratic Leader Tom Daschle. Both eventually took a pass and did not run for president. Senate Majority Leader Robert Dole, R-Kansas, did win the GOP nomination in 1996, but he was forced to resign his seat after it became impossible for him to run for president and oversee the Senate at the same time.

While Dole tried to create space from his time in Congress on the presidential campaign trail – he was first elected to the House in 1960 and Senate in 1968 – the former Majority leader was unable to shake the label as a Washington insider.

When Dole delivered his final Senate speech in June 1996, he praised the institution and acknowledged its imperfections.

“I would no more distance myself from the Senate than I would from the United States itself,” Dole said. “This body is a reflection of America. It’s what America is all about. We come from different states and different backgrounds, different opportunities, different challenges in our life. And, yes, the institution has its imperfections and our occasional inefficiency. And we’re like America. We’re still a work in progress in the United States Senate.”

For McCain, and the scores of presidential Senate hopefuls before him, after losing there was a soft landing at a place of importance and power.

“After I got the nomination, I literally wasn’t able to vote for a long period of time,” said McCain, noting the drawbacks of a presidential campaign. “Fortunately, I lost and was able to make up for it.”

In addition to Cruz, Rubio and Paul, Sen. Lindsey Graham, R-South Carolina, Sen. Rob Portman, R-Ohio, and Sen. Bernie Sanders, I-Vermont, have all expressed interest in running for president in 2016. In all, 16 senators have served as president, but 13 of them held different positions at the time they assume that office.