Gallup released its latest report on Americans’ ideological leanings, and the results weren’t especially encouraging, at least not from a progressive perspective. Consider this chart:

The dark green line shows self-identified conservatives with a 41% plurality, followed by self-identified moderates at 36%. Liberals are a distant third, as they have been for a long while.

Matt Yglesias posts related data from the same poll, breaking this down even further. There are nearly twice as many conservatives (11% very conservative, 30% conservative) as liberals (15% liberal, 6% very liberal).

It’s important to keep some caveats in mind when looking at results like these. For one thing, the public’s understanding of what these words actually mean varies considerably, and not everyone who considers themselves “conservative” is on the same page as, say, Jim DeMint. For another, ideological identification often doesn’t match up well with policy positions.

And while we’re at it, one can look at the above image and note that liberals can be in the national basement while the American mainstream still backs Democrats in large numbers. In 2006 and 2008, for example, Dems enjoyed terrific success at the ballot box — and at the time, while the number of self-identified conservatives was a little lower than now, so too were the numbers of self-identified liberals.

But all of those caveats notwithstanding, results like these still paint a discouraging picture for the left and progressive governance in general. Indeed, the numbers help dictate much of how the parties operate.

Republican officials and candidates have a base of support that’s quite sizable. Democrats officials and candidates are equally cognizant of the fact that, nationally speaking, their base simply has fewer people. It helps explain why Dems are more eager to compromise and more willing to reach out beyond their base — they need to find more people.

John Cole is pretty discouraged about all of this.

Now, other polling shows that people genuinely support “liberal” policies, only if they are not labeled liberal. Hell, the majority of the public wanted tax increases in the debt deal, but we know what happened there. Will any Republicans be punished by the public for refusing to raise taxes? Of course not. Will Obama be punished for violating the beliefs of 21% of the public? I’ve got a blogroll ready to crucify him right now.

I don’t know how to turn this around. We’ve got crazy people running things, and a public that keeps electing them.

I don’t know how to turn this around, either, but I do know it directly affects candidates. Put it this way: at a national level, a Republican candidate expects to win over conservatives, who represent 41%, and then only needs less than a third of the moderates to get to 50%. A Democratic candidate can try to shore up the support of the nation’s 21% of liberals, but then needs to go out and make up the difference from moderates and conservatives.

Why does it seem national Dems don’t do nearly enough to keep the progressive base happy? I suspect this has a lot to do with it.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.