Based on Senator Michael Bennet’s behavior these last few months you could be forgiven for thinking it was he who is up for re-election in 2014, and not his Democratic colleague Mark Udall.

Generally ahead of a re-election campaign politicians make a concerted effort to look more centrist. While Udall has tried that with one-trick pony shows like his bipartisan seating plan for the State of the Union, Bennet’s votes on key issues are overshadowing Udall’s shallow efforts, pushing Udall further to the left just when he needs to tack right.

The latest split between the Colorado delegation in the U.S. Senate came last Friday when Senator Bennet voted in favor of the Keystone pipeline, while Senator Udall sided with his wife’s environmentalist organization — which pays more into the Udall family bank account than his Senate gig — and opposed the pipeline.

Reports The Denver Post‘s Allison Sherry:

WASHINGTON — The normally cohesive Democratic team of Colorado senators split votes late Friday in a non-binding measure endorsing construction of the Keystone pipeline. 

Sen. Michael Bennet supported the amendment and Sen. Mark Udall voted against it. The U.S. Senate approved the measure 62-37, all 45 Republicans and 17 Democrats voted yes.

A recent state Department report, which had no major objections to the project, stated that the proposed pipeline would cross three states and run 875 miles. This is a change from the original plan, which would have traipsed 1,384 miles through five states.

…This is the second time this year that Bennet, who chairs the Democratic Senatorial Campaign Committee, has struck out against the majority of his party.

In the wee hours of New Year’s Day, Bennet was among only eight senators who voted against the deal to avert the fiscal cliff.

We wonder how pissed Udall’s staff was at Bennet for yet another vote that embarrasses Udall. After all, isn’t Bennet, as head of the Democratic Senatorial Campaign Committee (DSCC) supposed to be focused on helping incumbents up for re-election like Udall?

While no high profile challenger has yet emerged to take on Udall, any vote that exposes Udall for the left wing, environmentalist he is can’t be seen as helpful.

Udall’s vote also begs the question — who does Udall represent? The people of Colorado, who support the pipeline and the thousands of jobs it would create, or special interests like the organization run by his wife and Al Gore — the Climate Reality Project (CRaP)?