The uninvited participation of a hurricane at next week’s Republican convention would be superfluous. Buffeted by powerful internal winds, the party may be flooded with cash, but it’s already kind of a debris-strewn mess.

Who would have imagined that Topic A, in the days before GOP delegates gather in Tampa, would be abortion? Certainly the thought never crossed the minds of the convention planners who intended this four-day infomercial to be a nonstop indictment of President Obama’s performance on the economy. But the old line about the relationship between the political parties and their candidates — “Democrats fall in love, Republicans fall in line” — is so last century.

Party leaders will blame Rep. Todd Akin, R-Mo., for airing his appalling views about “legitimate rape.” But if you discount Akin’s bizarre notions about female reproduction, he was only stating official Republican policy on abortion as laid out in the platform that delegates will be asked to approve on Monday: “The unborn child has a fundamental individual right to life which cannot be infringed.”

Presidential nominee Mitt Romney, who once was pro-choice, now says he is against abortion except in cases of rape or incest, or when the mother’s life is endangered. But his party claims to believe, as Akin does, that there should be no exceptions. Romney’s chosen running mate, Paul Ryan, agrees with Akin but now has switched into “whatever Mitt says” mode.

There is no way to tidy up these contradictions. For decades, since the Ronald Reagan era, the Republican playbook has been to patronize social conservatives in the primaries and the party platform on issues such as abortion — and then, upon taking office, do little or nothing for the cause. But social conservatives turned their frustration into activism and eventually gained a measure of power within the party that the GOP establishment finds highly inconvenient.

Anti-abortion crusaders expect the party to practice what it preaches, even though abortion rights are guaranteed under Roe v. Wade and public opinion is strongly opposed to an absolute ban.

Similarly, evangelicals expect GOP action on their belief that the wall between church and state should be demolished. All right, that’s my phrasing, not theirs. But I don’t know how else to interpret the aim of office-holders such as Akin, who has spent his 12-year career in Congress fighting to increase the role of religion in government. “At the heart of liberalism,” he once said, “really is a hatred for God.”

The Republican Party also welcomed the energy, enthusiasm and votes of the tea party movement. Was the GOP establishment ever really serious about staging a “second American revolution” or slashing the federal government back to what it was in 1789? Not on your life. The recent pattern is that government grows much faster under Republican presidents than under Democrats. You can look it up.

Patronizing the tea party and enlisting many of its adherents as candidates helped the GOP win an impressive string of victories in 2010 and take control of the House of Representatives. But Speaker John Boehner has been struggling ever since to control unruly freshmen to whom the unthinkable — triggering a catastrophic default on U.S. government debt, for example — sounds like a plan.

Tension between idealists and pragmatists is inevitable in politics, but the struggle taking place within today’s Republican Party is extreme. The GOP believes in limited government that stays out of our business and lets us live our lives — but also wants to police every pregnancy in the land. The party says it wants to cut wasteful federal spending — but also insists on showering the Pentagon with billions for weapons systems the generals don’t even want. The party says it wants to balance the budget — but endorses a plan, authored by Ryan, that cuts taxes for the wealthy without specifying the offsetting budget cuts that would be required to keep deficits from ballooning out of control.

Being a “big tent” party is never easy. The GOP, for all its divisions, is full of energy and passion. What unites the various factions is the task of defeating Obama, and on this point there will be no dissent in Tampa.

But why does the Republican Party seek power? What does it really stand for? What does it hope to accomplish? What kind of America does it envision?

Keep an eye on that storm track as Isaac plows toward Florida. Maybe the elusive answers to those questions are blowin’ in the wind.

Eugene Robinson’s e-mail address is eugenerobinson(at)washpost.com.