Maine: ME-2 probably would be competitive if the GOP put any money into it. The right type of Republican could very well take it if that happens.
New Hampshire: It is. Deal with it, TNVolunteer.
Connecticut: Either Jodi Rell is somehow the nominee, or the Democrat actively insults the State while eating a baby on live television. Even then, only maybe.
If it's a swing state, why does it never, you know, "swing" lol?
Anyway.
Tennessee
1. Democrats nominate a very conservative nominee while the GOP nominates a Collins- or Kirk-type Republican and the Republican candidate runs a god-awful campaign and it's a big Democratic wave.
2. A third-party candidate who acts as a spoiler.
Montana
1. It was pretty close in 2008, it's not THAT Republican. You'll probably need a big Democratic wave and a Joe Manchin/Joe Donnelly Democrat to win here. Clinton, though? Haha no.
2. See: Tennessee
Kelly Ayotte, Judd Gregg, Frank Guinta, and probably Chris Sununu say hi