Also the farm crisis was still going on even into the early 90s. It's why Dukakis was so competitive in Montana + places like The Dakotas even as he got walloped Nationwide.
Should also be noted that the logging, paper, and pulp industries suffered greatly in the late-80s/early-90s. I would assume the Republican association with CAFTA and then NAFTA was perhaps a bit unpopular and voters may have been attracted to Perot's anti-free trade stance and Clinton's promises to renegotiate parts of the deal. I'm not an expert on Montana's economy but I am pretty sure they were in heavy competition with Canada on this front
