For the good of the whole country, the most important reelection campaign in the U.S. Senate is that of Republican Susan Collins of Maine. Collins is even more important for the good of Maine.

Collins faces a tough, strangely well-funded challenger this year in liberal Democrat Sara Gideon, the speaker of Maine’s House of Representatives. Gideon is running what, by official measure of the Wesleyan Media Project, is one of the nation’s most negative Senate campaigns, with 49.7% of her ads being of the “pure attack” variety. It’s a departure from Maine’s tradition of less-nasty politics — and bizarre against Collins, whose 24-year career has made her the epitome of old-fashioned, bipartisan graciousness.