A man walks to use a voting booth March 1, 2016, at one of the Virginia primary election polling stations at Colin Powell Elementary School, in Centreville, Virginia.
Voters in a dozen states will take part in "Super Tuesday" -- a series of primaries and caucuses in states ranging from Alaska to Virginia, with Virginia the first to open its polling stations at 6:00 am (1100 GMT).  / AFP / PAUL J. RICHARDS        (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)
PAUL J. RICHARDS/AFP/Getty Images
A man walks to use a voting booth March 1, 2016, at one of the Virginia primary election polling stations at Colin Powell Elementary School, in Centreville, Virginia. Voters in a dozen states will take part in "Super Tuesday" -- a series of primaries and caucuses in states ranging from Alaska to Virginia, with Virginia the first to open its polling stations at 6:00 am (1100 GMT). / AFP / PAUL J. RICHARDS (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)
Now playing
03:42
Can GOP turn Pennsylvania red in 2016?
Green Party presidential nominee Jill Stein waits to be introduced prior to a press conference at the National Press Club August 23, 2016 in Washington, DC.
Win McNamee/Getty Images
Green Party presidential nominee Jill Stein waits to be introduced prior to a press conference at the National Press Club August 23, 2016 in Washington, DC.
Now playing
01:44
Jill Stein raises millions for recount
Former Democratic US Presidential candidate Hillary Clinton speaks to staff and supporters at the New Yorker hotel after her defeat in the presidential election November 9, 2016 in New York. / AFP / Brendan Smialowski        (Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images)
BRENDAN SMIALOWSKI/AFP/Getty Images
Former Democratic US Presidential candidate Hillary Clinton speaks to staff and supporters at the New Yorker hotel after her defeat in the presidential election November 9, 2016 in New York. / AFP / Brendan Smialowski (Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images)
Now playing
02:14
Scientists urge Clinton to call for recount
LYNDEN, WA - MAY 07: Republican presidential candidate Donald Trump gives a speech during a rally at the The Northwest Washington Fair and Event Center on May 7, 2016 in Lynden, Washington. Trump became the Republican presumptive nominee following his landslide win in Indiana on Tuesday. (Photo by Matt Mills McKnight/Getty Images)
Matt Mills McKnight/Getty Images North America/Getty Images
LYNDEN, WA - MAY 07: Republican presidential candidate Donald Trump gives a speech during a rally at the The Northwest Washington Fair and Event Center on May 7, 2016 in Lynden, Washington. Trump became the Republican presumptive nominee following his landslide win in Indiana on Tuesday. (Photo by Matt Mills McKnight/Getty Images)
Now playing
03:25
Donald Trump's wild ride
Now playing
01:46
Trump's challenges in the Middle East
donald trump undocumented immigrants crime fact check origwx ty_00013807.jpg
donald trump undocumented immigrants crime fact check origwx ty_00013807.jpg
Now playing
02:47
Fact checking Trump on crimes by immigrants
Mark Makela/Getty Images/Lintao Zhang/Getty Images
Now playing
01:26
Trump vs. the tape on Obama and the protester
Now playing
01:28
Trump compares Clinton email probe to Watergate
Members of the Secret Service rush Republican presidential candidate Donald Trump off the stage at a campaign rally in Reno, Nev., on Saturday, Nov. 5, 2016. (AP Photo/John Locher)
John Locher/AP
Members of the Secret Service rush Republican presidential candidate Donald Trump off the stage at a campaign rally in Reno, Nev., on Saturday, Nov. 5, 2016. (AP Photo/John Locher)
Now playing
01:20
Donald Trump rushed off stage by Secret Service
AFP/Getty Images
Now playing
02:16
Trump reads letter from Patriot's coach at rally
US Republican presidential nominee Donald Trump speaks during rally at the Atkinson Country Club in Atkinson, New Hampshire on November 4, 2016.
Mandel Ngan/AFP/Getty Images
US Republican presidential nominee Donald Trump speaks during rally at the Atkinson Country Club in Atkinson, New Hampshire on November 4, 2016.
Now playing
01:56
Trump on US officials: 'What a group of losers'
donald trump nice and cool pensacola fl bts_00001523.jpg
donald trump nice and cool pensacola fl bts_00001523.jpg
Now playing
00:49
Trump's mantra in campaign's final week: Stay on point
donald trump nice to hillary clinton and democrats orig cm_00000000.jpg
donald trump nice to hillary clinton and democrats orig cm_00000000.jpg
Now playing
01:52
Audio of Trump praising the Clintons and Democrats
cuomo lewandowski hillary clinton email exchange newday_00002327.jpg
cuomo lewandowski hillary clinton email exchange newday_00002327.jpg
Now playing
01:28
Cuomo grills Lewandowski on Clinton email 'hypocrisy'
Now playing
01:49
Meet the other Hillary Clinton and Donald Trump

Story highlights

Trump has broad support in the state's rural and western areas

His campaign has also started to advertise in the state

(CNN) —  

For Donald Trump, winning the state of Pennsylvania is an uphill fight.

But if he takes the Keystone State, it likely comes with the keys to 1600 Pennsylvania Avenue.

“There are 800,000 more active Democrats than Republicans here,” said Terry Madonna, director of the Franklin Marshall College Poll and the sage of Pennsylvania politics. “The fact of the matter is Donald Trump does have a tough battle. I’m not saying he can’t win, but I’ll tell you what, if he did, the presidential race is over.”

The latest Muhlenberg College/Morning Call poll has Clinton with a comfortable 9-point lead over Trump but Madonna says the race is likely much closer.

“This election, his average in polls, has not been 5% or below for four months. And that’s huge,” he said.

Trump and his running mate, Indiana Gov. Mike Pence, have returned to the state often – nine visits between the two of them so far, with more on the way.

The campaign has also started to advertise in the state. After spending a sum total of zero on TV advertising through August, Trump has now spent nearly $3 million dollars on an advertisement highlighting immigration and security concerns.

Clinton, meanwhile, is taking no chances. Her campaign opened its 55th office in the state this week, she currently has more than 300 campaign organizers – and expects many more by Election Day – and she and her running mate, Virginia Sen. Tim Kaine, have been here 11 times, not including the party’s convention, which was held in Philadelphia. Clinton has also spent four times that of Trump, around $12 million, on TV advertising in Pennsylvania.

Trump has made a play for Pennsylvania based on broad support in the rural and western areas of the state. But he needs to compete in Philadelphia and the surrounding suburbs, where a third of the states’ voters live, if he hopes to turn the state red.

“If he loses the Philly suburbs by a few thousand voters, then fine,” Madonna said, “but he can’t lose by six figures. He won’t be able to make up the difference.”

Both campaigns have descended on Philadelphia and the surrounding counties to register voters and motivate them to vote. Hoping to appeal to women and moderates, Trump announced his childcare initiative in Aston just west of Philadelphia.

In the same week, President Barack Obama, Clinton’s strongest surrogate, made his first solo campaign appearance for her in Philadelphia trying to motivate young and African-American voters.

Philadelphia and the surrounding areas cannot be underestimated. In 2012, Mitt Romney won 54 of Pennsylvania’s 67 counties but still lost the state to Obama by 5.5% because of the heavy Democratic turnout in Philadelphia, the surrounding counties and the other Democratic stronghold, Pittsburgh.

Though a Republican presidential candidate hasn’t won Pennsylvania since 1988, it is often a battleground because most presidential contests here were won by 5 or 6 points. Obama’s 10-point advantage in 2008 was a blowout.

Voter registration across state was strong in July and August, actually running ahead of registration efforts in 2008, which was a banner year. Democrats have registered some 418,000 voters so far this year to Republicans’$2 321,000.

With the last day to register, October 11, looming, both camps have moved into high-gear to find new voters.

At a recent GOP get-out-the-vote effort in Stroudsburg, volunteers fanned out through neighborhoods looking for votes with instructions to be friendly and under no circumstances to engage in arguments with Clinton supporters.

Clinton launched a broad effort this week to get younger voters engaged. She spoke to a small group of students at Temple University, promising progress on a host of issues from student loans to job to climate change.

“If I’m in the White House,” Clinton said to great applause, “young people will always have a seat at any table where any decision is being made.”

Pennsylvania will be a test for Clinton’s enormous campaign operation versus the enthusiasm of Trumps’ most ardent supporters. With no early voting in the Keystone State, the race here will go all the way to November 8.

CNN’s Gregory Wallace, Jeremy Harlan and Peled Shachar contributed to this report.