There may be more to it that the first glance reveals.
Michigan's 6th House District is classified as "Safe Republican" by Stephen Wolf at DKos Elections. It is an R+1 according to Cook PVI. The current inhabitant of Congress from MI-06 is GOP Rep. Fred Upton, who has been there since 1992. (First elected from MI-04 in 1986)
Republican+Republican+Republican=Republican, right?
Hold on a second.
Paul Clements is a professor of political science at Western Michigan University in Kalamazoo. He is also the presumptive Democratic nominee for the House seat in MI-06. Elective experience: none. PAC money support: low. But here's the reasons why it may all pan out anyway.
1. Money. Clements has already broken the Democratic record for fundraising in this district. Granted, he still trails Upton by a wide margin, but his money has mainly come from small individual donations. If he can make a show of strength with that money, state and national attention should follow.
2. Unopposed primary. He is the presumptive nominee for a good reason: Not a cent of Clements' money will have to go into fighting other Democrats for the nomination. The filing deadline in Michigan was April 22, and he is the lone Dem in the district. Other, "more winnable" seats in Michigan have a contested primary (MI-08, MI-11).
3. Recent electoral/legislative history. MI-06 went 50-49 for Romney in 2012, and Upton got 55% that year. Upton has usually been re-elected with numbers in the 60% and up range, 55% is actually a low water mark for him. In prior years, though, Upton had also been seen as a more moderate voice in the Republican Party. Since the Tea Party wave, he has been reliably behind the House leadership and all of their kooky adventures. Clements should be able to exploit Upton's move towards the right.
4. Windfall effect. A strong showing by Mark Schauer in the Governor's race, and Gary Peters for Senate, would be a big boost to Clements, especially if he has done everything right by then and shown voters that he can potentially win. Also, the ace up the Democrats' sleeve is the proposed ballot question to raise the state's minimum wage. It's not quite there yet, but if that makes it to the November ballot, the winds could shift fairly quickly.
I am not yet ready to say that a win by Paul Clements is probable, as there are far too many x-factors that have to go the right way between now and November. But I am confident that a Clements win is possible.
The DCCC would be wise to sneak some cash into MI-06 and increase the odds a bit.