Erica Grieder wonders why Republicans always support their most conservative policies and political candidates with vigor, while Democrats generally shy away from full-throated support of their most liberal policies and candidates:
There seems to be a certain temperamental difference between conservatives and Republicans on the one hand and liberals and the Democrats on the other. In broad strokes, Republicans, especially of the tea-party stripe, are typically proud, at least unapologetic, and sometimes belligerent about their beliefs. Democrats, in contrast, seem to adopt the defensive position by default.
....Why are Democrats more anemic? One thought comes from the liberal journalist Thomas Frank. Writing in Harper's, Mr Frank argues that while Republicans respond to their base, Democrats have a misbegotten faith in a "Magic Middle" of centrist ideas that are tolerable, at least, to most Americans.
....I'm not sure whether Mr Frank intends this as an ideological explanation: Democrats see an intrinsic value in bipartisanship and are therefore disposed to its promotion, even if it requires some concessions from the liberal side. If so, I'm not sure I entirely believe it.
Nope, there's no reason to believe this. The real explanation, at least for the past few decades, is much simpler: about 40% of the American population self-IDs as conservative, compared to only 20% who self-ID as liberal. You can argue all day long about what people really mean when they tell pollsters they're conservative, and you can argue all day long that liberals need to do something to change this instead of simply accepting it, but for any politician running for national office in the here and now, this is just the lay of the land. A hardcore conservative with hardcore conservative beliefs can count on a pretty big base of support right from the start, while a hardcore liberal candidate can count on bupkis. Conservative Republicans can win. Liberal Democrats generally can't unless they're running in very liberal congressional districts. If you're looking for a reason why liberal politicians tend to compromise more, you really don't have to look much further than this.