People protest in opposition to something.  When those opponents promise something particularly egregious, it’s easier to convince your supporters of a real threat and the necessity of taking to the streets.

That’s why social movements activate their opponents.  Every potential success for one side is a cause of mobilization and fund raising on the other side.

When some evangelicals have determined that the day of rapture approaches, quitting jobs to get their lives in order, secular folks have seen an opportunity to put their views forward.  Ambreen Ali (Roll Call) reports that activists who want to take God out of government are using Harold Camping’s prediction of Rapture this weekend to demonstrate their claim: religion is a bad guide for decisions on matters of public policy.

If true Christians remain on Earth next week–or at least in the United States, the secularists will trumpet their superior judgment and try to build on their more accurate prediction (life on Earth will continue).  Odds are with the secularists this time; Camping predicted the rapture at least once before–in 1994.

In this case, it’s not an opponent’s threat so much as its foolishness that allows organizers to mobilize their base.

Is this also the case with Rep. Paul Ryan’s budget proposal?

Last week liberal activists appeared to heckle House Majority Leader Eric Cantor, who was speaking at Virginia Commonwealth University.  They challenged his (and his party’s) support for a proposal that would turn Medicare into a voucher program.  Politically, this bill is likely to be as big an embarrassment as the specific prediction of the end of days.  Democrats are going to talk about it whenever they can.

Republicans are going to try, desperately, not to talk about it.  When former Speaker of the House Newt Gingrich kicked off his presidential campaign by criticizing the bill, he was quickly and severely chastised by his party, from the leadership to the grassroots.  Gingrich had said that the Medicare proposal represented a radical change that wasn’t good for the country.  He was right, but he backed off the position quickly, seeing that he had hurt his chances at generating activist support at the grassroots and campaign funds from Republican interests.

One version of the Tea Party is becoming a veto force within the Republican Party, filtering out heterodox ideas that actually might play better with mainstream America than Tea Party orthodoxy.  This happens through the long long primary process, in which prospective candidates for the Republican presidential nomination have to demonstrate their vigorous attention to the most committed of the activist zealots at the grassroots.

Primaries for other offices are also a contest in which the issue activists can win.  Voter turnout is low in primary elections, skewed to the most committed in each party.  By launching primary challenges, movement activists can keep their issues visible, and can try to force conversions among elected officials.  So, Republican Indiana Senator Richard Lugar, a conservative in any other election (and he’s won six Senate elections), is facing a primary challenge from Richard Mourdoch, whose chief qualification is signing an anti-tax pledge that Senator Lugar has, thus far, refused to sign.

The primary challenge might convince Lugar to change his mind–or it might replace him with a purer alternative.   (Tea Partiers had already signed a letter asking him not to run for a 7th term.) Either way, it makes it easier for Democrats to play to the center of the political spectrum.  For social movements, it’s the purity versus pragmatism dilemma that social movements in America always confront.

For Democrats, the increased influence of electoral enforcers and filters within the Republican Party appears like an unexpected gift.