The following is a guest post by Joshua Spivak, a lawyer and a research fellow at the Hugh L. Carey Center for Government Reform at Wagner College.

With Republicans making a serious push to take over the Senate in November, a rare but important development may prove to be the key to the post-2010 Congressional landscape: the Senate may feature two elected members not beholden to the major parties — Independent s Joseph Lieberman and Charlie Crist.

In a closely divided Senate, having two Independents could play an outsized role as powerbrokers and creators of a moderate bloc. It would also be only the second time since World War II that two Independents occupied the Senate.

Successful Independents are very rare in high-level American legislative politics. Instead, they have been much more successful in winning gubernatorial races despite the fact that the Senate has twice as many seats available. In the last two decades alone, Minnesota, Maine, Alaska and Connecticut have all elected Independents. In the 2010 elections, there are at least three serious Independent gubernatorial contenders.

While there have been a number of Independent Senators in recent years, only Vermont’s James Jeffords was able to have any real impact, thanks to switching control of the chamber when he moved from the Republican side of the aisle. Nearly all of these Independent s have been men who left their previous party during midterms in a huff, either for personal pique or for political purposes. These senators then either quickly align with the opposition party.