There's a reason Colorado's 4th Congressional District is bound to land on a lot of national watch lists in 2010.

Rep. Betsy Markey, D-Fort Collins, swiped the seat from Republican Rep. Marilyn Musgrave, R-Fort Morgan, in 2008 - and with a 12 percentage-point margin that stunned even the most optimistic Democrats. It flew in the face of the GOP's 36,000-voter registration advantage in the 4th District, where unaffiliated voters lean to the right and still outnumber Democrats.

On paper at least, it's the type of traditionally-conservative territory Republicans are hoping to reclaim once the honeymoon ends for Democrats who came to power during a nationwide wave for "change."

History gives the GOP some hope for the next time around.

The midterm congressional election two years into a new president's first term has almost always meant net losses in congressional seats for the new party in the White House.

"Why?" History News Network editor Rick Shenkman wrote in 2006. "This is mainly because, in the midterm election, the weak candidates who rode in to victory on the coattails of their party's presidential candidate two years earlier find it difficult to win when they're running for president on their own."

Under President Bill Clinton, Democrats gained five House seats in the 1998 midterm elections. But that was his second term. His party was punished by Newt Gingrich's "Republican Revolution" in 1994, midway through the first term.

Markey can argue she's stronger than most "wave" election victors, since she outperformed President Obama throughout her district and beat Musgrave even in some counties that voted Republican in the presidential contest. But that was 2008, and the GOP hopes the next midterm election looks a lot more like 1994.