In Michigan’s seventh congressional district, Republicans are all frowns this morning. The Detroit Free Press has released a poll of 400 likely voters, in which the Democratic incumbent, Rep. Mark Schauer, leads his Republican opponent, former Rep. Tim Walberg, 45 to 39 percent. (The margin of error is 5 percent.) Voters are splitting their tickets between the popular Republican gubernatorial candidate, Rick Snyder, and the Democrat. Walberg also has a problem with independents:

In the EPIC-MRA poll, self-described independent voters gave Schauer an edge – among them, he led Walberg 45%-28%. Geographically, the district varies greatly, with voters in Calhoun, Eaton and Washtenaw counties giving Schauer a big edge. He also held a slim 41%-36% lead in Jackson County, which is considered critical.

Still, Schauer has been in office for only one term (he beat Walberg in 2008). He’s the second Democrat to represent the district since World War I. And Walberg initially won the seat by ousting the moderate incumbent, Joe Schwartz, in the Republican primary. In other words, the district seems pretty conservative. Precisely because it’s so conservative, however, the Detroit Free Press sees this district as a must-win for the GOP:

Most political pundits expect this to be a watershed election in which Republicans could regain control of the U.S. House of Representatives by picking up more than 40 seats nationwide, and the Michigan 7th has been considered a tossup throughout. If Republicans can’t retake the seat, it could hurt their overall chances of winning the House.