WASHINGTON — All signs point to a close finish in Pennsylvania's critical U.S. Senate race between Sen. Pat Toomey (R., Pa.) and Democrat Katie McGinty, with supporters of each saying their candidate can win — but no one firmly assured.
Four public polls out this week showed McGinty with leads ranging from one to six percentage points, and one Pennsylvania Republican familiar with private polling said that lines up with what the GOP sees internally. Other Republican operatives said the race is effectively tied.
Toomey is faring better with suburban moderates than Donald Trump is. But some Republicans worry his appeals to the middle could cost the senator with his conservative base. Republican groups are rushing in with last-minute money for ads. Democrats are pouring in cash, too.
Hillary Clinton has built a robust get-out-the-vote operation expected to aid her and fellow Democrats. Toomey has carefully targeted swing voters who might support Clinton for president while still backing a Republican for Senate.
In a contest that might not have a winner until late Tuesday night, here are key areas to watch as returns roll in:
Philadelphia: Winning starts here for Democrats. In 2012 President Obama and Sen. Bob Casey each came out of the city with a nearly 500,000 vote advantage. But this year, preliminary results from states with early voting suggest that African-American turnout is down, a worry for Democrats.
The party is pulling out all the stops to try to avoid that concern in Philly: McGinty and U.S. Rep. Jim Clyburn (D., S.C.), the highest-ranking African-American in Congress, met with black clergy members Wednesday. On Monday Philadelphia will get a visit from not just Hillary and Bill Clinton, but from the president and Michelle Obama as well.
Putting all four of those names on one stage the night before Election Day sends a message about how critical Philadelphia is to their hopes, and to Democrats up and down the ballot. (It also reflects Pennsylvania's lack of early voting and emphasis on Election Day itself).
McGinty is campaigning with Clinton Friday in Pittsburgh and with Biden in Bucks County Saturday, and on Friday she released online ads featuring praise from Michelle Obama — all part of a clear push to build enthusiasm and tie her to what Democrats hope will be a blue surge at the finish line.
The collar counties: Here is where elections typically swing in Pennsylvania. Bucks, Chester, Delaware and Montgomery counties accounted for nearly one out of every four votes in the 2012 election. Republicans don't have to win here — but they do have to keep it close.
Consider: In 2010, Toomey lost the four counties by just 22,000 votes and eked out a statewide victory over Joe Sestak. Two years later, Casey won the four suburbs by roughly 160,000 votes and cruised to a blowout win.
Recent polls show McGinty faring well in southeastern Pennsylvania, but the surveys fold in both Philadelphia and the suburbs, so it's impossible to discern how much of her strength comes from the deep blue city and how much comes from the more moderate suburbs.
Toomey, who has worked hard to moderate his image, is running better in this area than Trump. His campaign has focused its get out the vote operation on Clinton supporters who also might also vote for the Republican senator. But it's not clear if he can keep it close enough.
The conservative base: One question for Toomey is if his work to win voters in the center has hurt him on the right.
Throughout the campaign, some Pennsylvania Republicans worried that Toomey's support of tougher background checks on gun purchases — the centerpiece of his appeal to moderates — will hurt him in other parts of the state, where conservatives look warily upon new gun laws. Those concerns may be exacerbated by Toomey's refusal to endorse Trump, another step seemingly aimed at maintaining his appeal to swing voters. Will fervent Trump supporters refuse to vote for the senator?
It may only be a small percentage of voters who question Toomey, Republicans said, but in a tight race, even a little bleeding from the base could affect the outcome. Other Republicans, however, say these fears are overblown and not borne out by polls.
Two of the recent public surveys show conflicting evidence as well: A Monmouth University poll found Toomey running six percentage points behind Trump in western PA, while CNN found the two had the same level of support there.
Who stays home? As Donald Trump's poll numbers plunged earlier this fall, Republicans worried that some disgusted conservatives would sit out the election — sapping votes that Toomey needs. But the renewed FBI examination of emails from Clinton's time as secretary of state have flipped those concerns.
Republicans believe that the new questions will energize their voters, while possibly rekindling doubts among some reluctant Democrats. It seems unlikely to be enough to turn Pennsylvania red in the presidential race — but even small erosion might be enough to hurt McGinty.
You can follow Tamari on Twitter or email him at jtamari@phillynews.com.