PHILADELPHIA, Pennsylvania -- Good Wednesday morning. Politics Nation comes to you live from Philadelphia today, where between stuffing our faces with good pretzels, good shaved pork sandwiches and good cheese steaks, we'll be covering a presidential debate. A few hours south of us, here's what Washington is watching:

-- The Senate continues to spar over a bill correcting a recent highway and transportation measure, while the House takes up student lending, debt relief and some environmental measures. President and Mrs. Bush, as well as Vice President and Mrs. Cheney, welcome Pope Benedict XVI to the White House before meeting together in the Oval Office. Today just happens to be Benedict's 81st birthday as well. Later today, Bush makes remarks on climate change from the Rose Garden on what is supposed to be a beautiful day, and Cheney attends the annual Radio-TV correspondents' dinner in Washington.

-- In an increasingly contentious nomination battle, a slew of new polls out move Hillary Clinton's advantage in the Keystone State to an 8.6-point margin, per the latest RCP Pennsylvania Average. Click on that link, and take a look at the graph. Barack Obama was in the middle of a huge and stunning comeback, but now that return looks stalled. And don't be fooled; Obama is trying to win the state, dumping millions in advertising, spending time here and investing in an infrastructure meant to hold the margin as low as possible. But as the two Democrats prepare to meet at Constitution Hall, it is Clinton who is in the clear, commanding lead with six days to go.

-- Should Clinton pull off the ten-point lead many thinks she will need to declare a realistic victory, the media will likely blame Obama's comments that small-town Pennsylvanians are "bitter" and "cling" to their guns and their faith. But the new polls out in the last twenty-four hours don't back that up, yet. Of the three in five polls that make up the latest RCP Average conducted after the remarks came to light, SurveyUSA shows the race tightening by four points while Rasmussen and Strategic Vision show the race widening from a five-point Clinton advantage to a nine-point margin. Strategic Vision, though, should be seriously discounted; their questionnaire shows they asked about the horse race matchup after they asked about Obama's comments (31% agree, 55% disagree), a seriously effective way of skewing the sample.

-- The two other polls involved in the latest RCP Average each show a tight race just outside the margin of error. One, from the LA Times and Bloomberg, has the race favoring Clinton by just five points, while another, from Quinnipiac University, has Clinton leading by six points, the same margin as their survey conducted a week earlier. Both polls were in the process of being conducted when news of the comments broke, but that they are narrow margins says something, perhaps, about the media's overreaction. Where does the story go next? The Fix has the rundown, including the notion that Obama may owe a kiss of the Fisherman's Ring to a certain Pope if that story dominates cable news coverage over the next few days (including the post-debate mass at the Nationals' new ballpark).

-- Those comments, though, will likely be the bedrock of tonight's fracas at the Constitution Center, a debate which broadcasts live at 8 p.m. Eastern on ABC. The Obama campaign is complaining that media is overhyping the story, giving it more play than it's worth, and they may have a point: Yesterday, during a taping of Hardball at Villanova University, John McCain was asked about Obama's remarks, and it was among the first questions thrown at Hillary Clinton on Sunday at a forum at Messiah College (which we wrote was a Catholic school; it's an Evangelical school, and we regret the error). Clinton is making as big an issue out of it as possible, hammering Obama in advertisements running in Pennsylvania, but is anyone else? Perhaps Tuesday is the test.

-- The real story of Pennsylvania is the amount of advertising going on, especially in the Philadelphia market and its suburbs. A tight state Senate primary and a contest for the Democratic nomination for State Treasurer are showing up on television, but interspersed throughout, in an almost Iowa- or New Hampshire-esque level of saturation, are Obama ads. He dominated the Flyers' playoff win over the Washington Capitals last night, ran ads during the Philles' win over the Houston Astros, and has been on every cable station in between. Last week, Obama spent $1.4 million on ads in Philadelphia alone, reports the Post's Matthew Mosk, compared with just $547,000 for Clinton. On cable in the next week leading up to the vote, the gap could be closer to a five-to-one advantage for Obama.

-- Some of the advertising is nasty, most of it is positive. In truth, the most negative ads we heard yesterday from both candidates came on the radio, where Obama accuses Clinton of taking money from oil companies and Clinton hits back, saying that's illegal and accusing Obama of distortions. But tonight's throwdown in Philadelphia promises to provide fireworks for one reason or another. Either Clinton is the feisty debater she was before voters in Ohio and Texas went to the polls, or she's the bland, boring debater who looked like she had given up before New Hampshire. In both cases, tonight is all about Clinton's performance, and that has to make Obama nervous. But he's handled it before, and tonight could prove another opportunity to declare him the front-runner.

-- Meanwhile, as we mentioned, McCain stopped by Villanova University yesterday to film Hardball on MSNBC. McCain was giving his interview while Michelle Obama was rallying students at locals at a stop at Haverford College, just down Lancaster Street a tick, a stretch of road that also includes St. Joseph's and Bryn Mawr. But McCain packed the place, hours after giving a speech on the economy on the Pittsburgh campus of Carnegie Mellon University in which he called on a summer holiday for a gas tax, as AP's ever-present McCain reporter Liz Sidoti writes. McCain's other economic initiatives included raising Medicare premiums on the wealthy, a revamped and simpler tax code and a one-year suspension of discretionary spending increases. The proposals are pretty basic McCain, but they're a starting point in the battle to define him on the economy.

-- Comeback Of The Day: As promised, former Arkansas Governor Mike Huckabee has no intention of going away. As the count-down clock on Huckabee's website expired yesterday, the last man standing against McCain launched HuckPAC, a vehicle that will allow Huckabee to stay involved in the process, backing candidates and building good will toward a presidential bid in 2012 or 2016. Perhaps unsurprisingly, one of Huckabee's first three "featured candidates" is Bob Clegg, a New Hampshire state senator vying to unseat Democratic Rep. Paul Hodes. How many more Republicans from Iowa and New Hampshire are going to get help?

-- Today On The Trail: It's a light day as candidates prepare for tonight's debate. Obama is meeting with Jewish leaders in Philadelphia this morning, and Clinton's only public event is a Building Trades conference in Washington before flying up to Philadelphia. Michelle Obama has events planned for Evansville, Indianapolis and Anderson, Indiana, while Bill Clinton is in Indiana, Pennsylvania (don't get confused), Kittanning, Clarion, New Castle and Cranberry Township, all on the western side of the state near Pittsburgh.