Thus far, Democrats have opposed Boehner almost unanimously, saying he has made no meaningful concessions. That leaves Boehner at the mercy of his 232-member GOP caucus, where conservative hardliners prevent him from passing any measure they oppose.
In past decades, congressional leaders often crafted bipartisan solutions in the political center to resolve tough issues. Then, however, more House members came from politically competitive districts. Taking a more centrist, cooperative stand often helped these lawmakers win re-election.
Now, far more House members come from firmly conservative or firmly liberal districts. Their only election vulnerability is in their party's primaries, when ideological purists might accuse them of being unacceptably cooperative with the other side.
The previous two government shutdowns, in the mid-1990s, ended fairly quickly. Many House members then faced greater threats in a general election than in a primary, because their districts were politically balanced. In 1995, for instance, 79 House Republicans represented districts carried by Democrat Bill Clinton in the previous presidential election, according to a National Journal analysis.
Today, only 17 House Republicans come from districts that Obama won.
The dramatic decline of House GOP moderates — who once came to Congress in big numbers from the Northeast and Midwest — was made clear this week when a supposed moderate insurrection drew only two votes against a Boehner-backed budget measure.
In a similar vein, moderate-to-conservative House Democrats, especially from the South, have virtually vanished.
The result is a House full of lawmakers confident in the rightness of their views, and in the likelihood of their re-election next year.
And therefore, no matter how many times the Democratic-controlled Senate rejects efforts to curtail "Obamacare," Republicans keep trying.
"We want them to admit there are problems with Obamacare," said GOP Rep. James Lankford of Oklahoma, where Obama won only 33 percent of the vote last year. As for how long the shutdown might last, he said: "I have no idea."
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