There is no question there is a Republican wave building throughout most of the country that will probably deliver the House of Representatives to the Republicans. But polling just this week is showing that optimism for huge GOP gains in the U.S. Senate may be fading.

If the GOP fails to win the Senate in this wave year, Tea Party candidates, especially those favored by the California-based Tea Party Express, will be to blame.

The Tea Partiers have already cost the GOP one Senate seat, in Delaware, where they managed to knock off moderate Rep. Mike Castle in the primary – he being the only Republican who has carried the state in decades. Christine O’Donnell, the Tea Party victor, has turned out to be the most ludicrous candidate for Congress in either party this year. Not only has she had to deny she is a witch – apparently she does not actually belong to a coven – but in a recent debate, she did not even know what the First Amendment was all about.

Liberal groups, led by their friends in the media like CNN, are making O’Donnell the face of the GOP this year to frighten independent voters away from Republican candidates. It may be working. In the neighboring Pennsylvania Senate race, safe for the Republican in the polls just a week ago, the Democrat has caught up. The same thing has happened in Colorado where the Tea Party Republican, Ken Buck, has shown such a case of foot in the mouth disease the appointed Democratic senator may actually win. That race is a toss-up today; it was leaning GOP a week ago.

But the two most interesting races are those where the Tea Party Express played a major role in the nominations, Nevada and Alaska. Senate Majority Leader Harry Reid is among the most despised office holders in Nevada history but he is hanging in there for re-election again Tea Partier Sharron Angle because of her extreme positions on issues like Social Security. In Alaska, Sen. Lisa Murkowski was defeated in the primary by a Tea Partier named Joe Miller. Miller has now been accused of numerous improprieties and Murkowski is running as a write-in candidate. Having two GOP candidates and one Democrat raises the possibility the Democrats could steal the Alaska Senate seat.

Democratic control of the Senate, and especially the Senate Judiciary Committee, is vital for coming Obama judicial appointments, especially for the Supreme Court. If the Tea Party candidates scare enough independents into voting Democratic in the next two weeks, the great 2010 Republican wave may evaporate like a summer shower.