Sen. Mark Udall, D-Colo., may face increasing headwinds from Obamacare as he tries to fend off a challenge from Rep. Cory Gardner, R-Colo., given that low enrollments in his state are likely to drive up insurance premiums for his constituents, many of whom lost their previous plans because of the health care law.

"With less than a month to go before the enrollment period ends for this year, fewer than 85,000 Coloradans have signed up for health insurance," The Colorado Observer's Mark Stricherz reports, noting that state officials projected that they would need 125,000 to 140,000 enrollees.

“Even in the worst-case scenario, insurers would still be expected to earn profits, and would then likely raise premiums in 2015 to make up the difference,” Stricherz quotes Kaiser Family Foundation analyst Larry Leavitt as predicting.

Quite apart from the issue of premium increases, the 84,881 enrollees is far below the number of people who lost their insurance plans because of Obamacare.

"Cancellation notices affected 249,199 people," Jo Donlin, director of external affairs for the state insurance division, wrote in a Nov. 14 email. One of those people was Gardner himself.

Udall is clearly worried about how Obamacare affects his re-election prospects. Donlin accused him, in that email, of trying to "trash" the state's cancellation figures. When CNN's Dana Bash asked him in January (before Gardner entered the race) if he would campaign with President Obama, Udall repeatedly refused to give a direct answer to the question.

"Coloradans are going to re-elect me based on my record, not the president's record," Udall told Bash.

Republican National Committee chairman Reince Priebus told the Washington Examiner that the GOP would be building a list of voters who have lost their plans as part of a 2014 election effort.

"Getting that information [on plan cancellations] and having good data as to who votes, who doesn't vote, voter registration, party affiliation, consumer characteristics, cross-referenced with that kind of information, I think, is important for us to have," Priebus said.