Missouri Republicans have just nominated a Senate candidate who appears to believe that the government’s college student loan program is the equivalent of Stage 3 cancer. Actually, he said “the Stage 3 cancer of socialism,” which is perhaps not the exact same thing. But I believe you get the idea.

This was a week after Texas Republicans nominated a Senate candidate who is worried about protecting the world’s golf courses from the United Nations. Republicans, I think you need to get a grip.

Meanwhile, the most cheerful place this side of Disney World is the Democratic Senatorial Campaign Committee. Sen. Claire McCaskill of Missouri, the Democratic incumbent, was regarded as the political equivalent of roadkill until the Republicans picked Rep. Todd Akin for her opponent. Now, the McCaskill campaign is doing a happy dance while Akin will be trying to explain that he thinks student loans are cancerous only when they come from the government rather than private industry.

This is not the kind of argument you really want to be having on your big primary win day. Also, Akin not only wants to keep the government out of the student loan business, his past votes suggest he also wants to see it steer clear of school lunches.

Before the primary, McCaskill ran an allegedly anti-Akin ad that cynics saw as an actual attempt to propel him to the front of the pack. It failed to mention the congressman’s principled opposition to the national School Breakfast Program, but instead denounced him as “too conservative” and an enemy of Planned Parenthood. Honestly, if you wanted to drive tea party voters to the polls, it was the next best thing to hiring a bus.

The tea party is once again giving Democrats a new lease on life. Not everywhere, of course. Tennessee Republicans seem to be happy with their incumbent senator, Bob Corker, while Democrats woke up on the day after their primary to discover that voters had nominated an anti-gay-rights activist named Mark Clayton, who, according to ClaytonforSenate.com, “works in insurance and is also writing a book intended as a scripture study aide.” A spokesman for the Tennessee Democratic Party, which is disavowing Clayton, theorized that he won because “his name was at the top of the ticket.”

We have been through this sort of thing before, Democrats. Remember Alvin Greene? The guy you accidentally nominated to run against Sen. Jim DeMint two years ago? The one who turned out to be facing felony obscenity charges? Didn’t everybody agree that from then on, if you gave the voters a ballot full of totally unfamiliar names, you would warn them which ones to avoid?

But mainly, the Republicans are the ones getting stuck with the unhappy surprises. Richard Lugar, the longtime senator from Indiana, was tossed out in a primary by a tea party favorite, Richard Mourdock, who went on to become involved in a controversy over whether or not he compared President Barack Obama’s auto industry bailout to slavery. We do not really need to resolve the issue, except to say that Mourdock is fond of making convoluted historical analogies and that he really, really did not like the auto bailout, despite Indiana’s rather large population of autoworkers.

Besides tea party upsets, one of the big trends this year is for Democratic Senate candidates in red states to demonstrate their independence by announcing that they are not going to the party convention. This is pretty much a no-brainer, since these events are really, really boring anyway, unless 1) You really like to eat finger food paid for by special-interest groups or 2) You really enjoy being in Southern cities with high humidity around Labor Day.

Skip the convention! Everybody’s doing it! Although Sen. Joe Manchin of West Virginia did seem to be going a little bit overboard when he refused to say if he’ll even vote for Obama.

“I am just waiting for it to play out. I am not jumping in one way or another,” Manchin told The National Journal. “I’m worried about me. I’ve said it’s not a team sport. You need to go out and work for yourself.”

You’ve got to give the man credit for candor. Manchin may be pretending to be more worried than he really is, given that the Republicans nominated a Senate candidate whose big media splash involved comparing no-smoking regulations to the Nazis’ actions. (“Remember Hitler used to put Star of David on everybody’s lapel, remember that? Same thing.”)

Next week we have Wisconsin, where former Gov. Tommy Thompson, the guy everyone expected the Republicans to nominate for the Senate, is in trouble thanks to a challenge from — yes! — the tea party. And will Connecticut Republicans nominate a former congressman with a reputation for bipartisanship or a businesswoman whose claim to fame is building a professional wrestling empire? Duh.