"We must emphasize that Democrats won control with CONSERVATIVE candidates. This country didn't sweep Liberals into office last night; each and every race was LOCAL. Rahm and Chuckie (I have to admit) were brilliant. They know in their heart of hearts that Americans are primarily conservative; but they know that under Speaker Pelosi, the newbies will wilt and comply. Look for investigations of Bush and Cheney. Look for a lower stock market. Eventually, though, the people who voted in these nitwits will finally see that Democrats are downright DANGEROUS."
You might say that the liberals were swept in with a moderate-conservative broom. It means that in this case a new broom sweeps dirty.