Democrats' lead fades in Colorado Senate race. Is state not so blue after all?

One of the most watched elections in the country right now wasn't originally supposed to be competitive.

The outcome of the race between Democratic incumbent Sen. Mark Udall and his Republican challenger, Rep. Cory Gardner, could end up determining which party controls the Senate. Senator Udall's early leads in the polls have dwindled until, in the past month, nearly every poll has showed Representative Gardner holding a slim lead.

A year ago, most political observers assumed that Udall would have a relatively easy reelection in a state that has been trending blue for some years. But a combination of antipathy toward President Obama (and Washington incumbents generally), a challenger who is more moderate than some recent Republican candidates, and a seemingly one-note campaign by Udall – focusing on women and reproductive rights – has changed the dynamics.

"It’s close, and could break either way," says Denver pollster Floyd Ciruli. "There’s clearly a feeling at the moment that Cory Gardner has the momentum."

So what happened in Colorado, a state that Mr. Ciruli and others were starting to see as "light blue," rather than purple? Part of Udall's challenge has been facing a Republican in a midterm election with a hugely unpopular Democratic president. Udall has done what he can to distance himself from Mr. Obama – so much that when the president came to Colorado this summer to raise money for Udall, Udall found a reason to stay in Washington – but it's been an uphill challenge.

Add to that the fact that the Colorado legislature, with both houses controlled by Democrats, enacted progressive legislation in the past few years that angered some Independent and conservative Coloradans.

"Local [factors] joined with national helped produce what you’re watching today," says Ciruli, referring to the conservative backlash. "Moderates and people in the middle have decided that’s the side they’re going to be on this time, that it's time to rein it in."

But observers also say that Udall hasn't helped matters by running a campaign that seems to be designed as a replay of the campaign that helped Democratic Sen. Michael Bennet eke out a win in 2010, despite lagging in the polls until the end. Back then Senator Bennet won, in large part, by focusing on women voters as well as reproductive rights. His opponent, Ken Buck, was a cultural conservative who believed abortion should be banned in all instances, and he made tone-deaf statements, once telling an audience they should vote for him "because I don't wear high heels."

In the end, women voted for Bennet by a margin of 16 percent, according to the exit polls, and were a big reason behind his victory.

Udall's advisers have clearly wanted to re-create that victory, and reproductive rights have been such a focus of Udall's campaign that his critics began calling him "Mark Uterus." Unlike with Bennet, the focus has turned into a negative for Udall.

"It's a case of the Democrats fighting the last war," says Peter Hanson, a political science professor at the University of Denver. "The Republicans have seen this strategy and were prepared for it."

Most notably, they put forward a stronger candidate in Gardner, who comes across as less extreme on social issues than Mr. Buck did. Despite past support for "personhood" amendments in Colorado (and support for a federal personhood bill, a fact that Udall doesn't let voters forget), Gardner chose not to support the current personhood measure on the ballot this November. He also took proactive steps, for example, calling for over-the-counter sales of birth control.

"Part of the Democratic strategy is to mobilize voters by making them fearful of what will happen to women’s reproductive rights if a Republican is elected," Professor Hanson says. "They're not as concerned about Cory Gardner."

And that focus on reproductive rights, at the expense of other issues, seems to have swayed others against Udall. In an endorsement that came as a surprise to many, The Denver Post, which endorsed Udall in 2008, came out for Gardner earlier this month. While the Post called Gardner "a fine man with good intentions," the paper brutally criticized Udall's focus on reproductive rights, saying that "his obnoxious one-issue campaign is an insult to those he seeks to convince."

But it's hardly a certain victory for Gardner. Almost all the polls show the race close enough to be within the margin of error, and two new polls sponsored by Democrats give Udall a three-point edge. While it's true that partisan polls often give an edge to their candidates, it could well be that – as Democrats claim – the nonpartisan polls are underrepresenting what Democratic turnout will be.

Almost everyone agrees that the election hinges on turnout at this point, and Democrats historically have a better voter mobilization operation in Colorado. New universal mail-in balloting may also help Democrats.

The outcome of the race, Ciruli says, will depend on whether Udall is able to get the full Democratic vote out of Denver and Boulder; whether Gardner is able to mobilize turnout in conservative bases like Douglas and El Paso Counties; whether Hispanic voters turn out or choose to stay home; and what happens in the three big swing counties – Arapahoe, Jefferson, and Larimer – where Democrats have had the edge in recent years.

"The question is whether voter mobilization can overcome an environment that currently favors Republicans," says Hanson.