The Republican Party's candidate for governor of Colorado believes that bicycle paths are "part of a greater strategy to rein in American cities under a United Nations treaty." The party's Senate candidate in Nevada wants to privatize Medicare and Social Security -- and has called for the United States to withdraw from the United Nations, though not because of the bicycle conspiracy. And the GOP's Senate candidate in Connecticut once climbed into a professional wrestling ring and kicked a man in the crotch.

I could go on, but you get the point. Democrats may be facing a tough fight this fall, but Republicans are giving them plenty of material to work with.

The big political story of the year may turn out to be the consequences of the GOP's foray into extremism and wackiness. It could be that the party acculturates its not-ready-for-prime-time candidates, harnesses the energy of the Tea Party movement and sweeps to a grand old victory. There is also the distinct possibility that the acute philosophical split within the party -- basically, a clash between bedrock conservatism and utter nonsense -- will hand victories to Democrats that they didn't anticipate and frankly might not deserve.

Anyone who doubts this assessment should reflect on the fact that major figures in the Republican Party are wasting valuable time and energy debating whether the 14th Amendment to the Constitution, adopted in 1868, should be repealed.

At issue is birthright citizenship -- the amendment's guarantee that children born here are automatically U.S. citizens, even if their parents are in the country illegally. It's hard to remember that as recently as three years ago, major figures in the Republican Party such as Lindsey Graham and John McCain were speaking out in favor of sensible, comprehensive immigration reform. But in today's GOP, which is energized by Tea Party passion, Graham and McCain want to hold hearings on whether birthright citizenship should be abolished. Many top Republicans have decided that taking a moderate, compassionate stance on illegal immigration -- even on the status of innocent newborns -- is just too big a risk.

This exercise in being tougher-than-thou on immigration has the potential to drive Latino voters into the waiting arms of the Democratic Party for years to come. More urgently, it can give Latinos a reason to go to the polls in November, and perhaps tip the balance in some tight contests.

In several high-profile contests, candidates who won nominations with fervent Tea Party support appear to be in the process of snatching defeat from the jaws of victory. The Colorado governorship, for example, would seem to be ripe for the Republicans' picking. But nominee Dan Maes' bizarre views about such things as bicycles and the United Nations threaten to deliver the race to Denver Mayor John Hickenlooper.

In Nevada, Senate Majority Leader Harry Reid seemed in danger of suffering a humiliating loss -- until the Republicans nominated the disastrously quotable Sharron Angle. Now it looks as if Reid may pull this one out, unless reporters take Angle's advice on how to do their jobs. "We needed to have the press be our friend," she told an astonished Carl Cameron of Fox News. "We wanted them to ask the questions we want to answer, so that they report the news the way we want it to be reported."

Not all of the GOP's internal issues involve the Tea Party. In Connecticut, Linda McMahon won the party's Senate nomination through one of the traditional routes: She bought it by spending part of her personal fortune, which comes from the WWE pro-wrestling empire. The problem is, ahem, the nature of the WWE wrestling empire -- and the fact that McMahon occasionally appeared as a character in the ring.

"Today the party of Bob Dole, Jack Kemp and Dick Lugar nominated a candidate who kicks men in the crotch, thinks of scenes of necrophilia as 'entertainment' and runs an operation where women are forced to bark like dogs," a Democratic Party spokesman wrote, in what promises to be just an opening salvo. Then again, association with pro wrestling may not be a deal-breaker at the polls. Just ask Jesse "The Body" Ventura, former governor of Minnesota.

Democrats would be foolish to take a single contest for granted, but Republicans would be equally foolish to assume that some kind of sweeping win in November is guaranteed. The GOP knows what the Democrats' campaign themes will be -- but it has no idea what some of its own candidates will say or do next.

eugenerobinson@washpost.com