Tonight, voters go to the polls in Pennsylvania's congressional and statewide primaries, and there are a number of races worth watching. Our guide to the key contests is below the fold, but first, here's a zoomable map of the Keystone State's new congressional districts:
• PA-Sen (R): A whole lot of Republicans have piled into this race for the dubious honor of getting creamed by Bob Casey, Jr. in November. The favorite at this point has to be former coal company owner (and, long ago, the elected supervisor of tiny Plumcreek Township) Tom Smith, who's gone from unknown to frontrunner the old fashioned way: by spending way more on advertising than anyone else. His main opposition has shaped up to be fellow rich guy Steve Welch, who has the backing of most of the local Republican establishment, since they view him as the most electable candidate for November.
Although Welch generally seems more moderate than Smith, both have been hitting each other in ads for the exact same sin: their shared history of having voted and contributed for Democrats in the past. Ex-state Rep. Sam Rohrer (who lost the 2010 gubernatorial primary to Tom Corbett) is also in the hunt, but has been a non-entity financially and hasn't advertised; the field is rounded out by David Christian and Marc Scaringi, who seem to appeal exclusively to the hardcore tea partiers and the social conservatives, respectively. Smith has a double-digit lead over the rest of the pack in his latest internal poll.
• PA-AG (D): Democrats have never won the attorney general position in the three decades since this became an elected position, but they're hoping this is the year that changes that. The two candidates in the primary are ex-Rep. Patrick Murphy (who lost in PA-08 in 2010) and Kathleen Kane, a former prosecutor from Lackawanna County. Murphy, popular among the netroots from his time in the House, is better-known in the Philadelphia market, but Kane (who is personally wealthy) has had enough money available to compete on the statewide airwaves, and she's sporting a nine-point lead in a recent internal poll.
• PA-04 (R): In this open-seat race to replace GOP Rep. Todd Platts, the two leading candidates appear to be state Rep. Scott Perry and York County Commissioner Chris Reilly. While neither candidate has fundraised impressively, if anyone has the edge, it's probably Reilly, who's been the beneficiary of spending by Sen. Pat Toomey's PAC. Reilly also had a small lead in the only public poll of the contest, but a majority were undecided, and Perry's managed to get on the air, too. So this could be anybody's game.
But there's one big "but." Though Critz and Altmire are both among the least progressive members of the Democratic caucus, they've amassed their records in very different ways. Altmire, a Blue Dog, has a reasonably liberal record on social issues but votes quite conservatively on economic matters. Critz tends toward the opposite, and in particular, he's a strong backer of organized labor. And that's where he's hoping to make up for his geographic disadvantage: He's virtually swept the unions when it comes to endorsements, and they're working hard for him. This race will be a big test of their muscle, as this region once used to be home to lots of union workers, but as coal mines and steel mills closed, far fewer remain. The most recent poll gave Altmire a narrow four-point edge, so while he is still the slight favorite, this is anybody's race.
• PA-17 (D): Republicans knew exactly what they were doing when they surrounded Rep. Tim Holden's home territory of Schuylkill County with much bluer turf. Even though Holden had long represented conservative districts and amassed a voting record to match, they knew he wouldn't opt for a swingier district (like the adjacent 11th or 15th)—where he might threaten a GOP incumbent—since Holden made it clear he'd run wherever Schuylkill wound up. That allowed Republicans to get Holden off their backs and create something of a Democratic vote sink. But it seems like Holden may have made a serious mistake, since he drew a challenge from the left from wealthy attorney Matt Cartwright.
All of a sudden, the very same centrism that allowed Holden to survive in such tough districts for so many years all became a big liability in this 57 percent Obama district, with Cartwright's allies hectoring Holden for his departure from the Democratic line. And just as if not more important, Cartwright is a well-known local litigator whose name has appeared on ads throughout his end of the district for years. (He's also self-funded quite a bunch.) So Holden wound up both at an ideological and a geographic disadvantage (he represents just 21 percent of the new 17th), and an unanswered Cartwright internal suggests that Holden is now the underdog in this race. He may yet pull this out, but there's a good chance he'll become only the second House incumbent this year to lose in a primary to a non-incumbent challenger.
• PA-18 (R): Republican Rep. Tim Murphy, who's represented Pittsburgh's southern suburbs and collar counties for a decade, is nobody's definition of a moderate, but apparently he's too labor-friendly—and not sufficiently committed to absolute austerity for the tastes of Beltway meddlers like the Club for Growth and FreedomWorks. They latched on to young former Hill staffer Evan Feinberg as a more conservative alternative in the primary, spending some money on his behalf. Feinberg hasn't gotten any traction, though, either in terms of polling or fundraising, and recent weeks have seen the purity patrols cutting their losses and mostly turning Feinberg loose.