Not quite. Montana is not an evangelical Conservative state like states in the deep south. It is more of a libertarian state and is majority pro-choice. Notice how Tester is strongly against gun control? That plays well in Montana.
It's not a religious right state, but that doesn't make it socially liberal. Montanans tend to be economically conservative, too.
Tester is hardly a liberal. He is against gun control and a lot of other things that liberals support.
I'm a liberal, and I oppose gun control. Tester is left-wing on almost every issue...
... although nobody would consider Tester an anti-globalization activist, his position on international trade is more in line with the protesters who shut down Seattle in 1999 than with the Democratic Leadership Council.In addition to the examples I gave above.