At the same time, an NBC News/Marist College poll released Tuesday found Democratic Sen. Mark Udall leading Republican Rep. Cory Gardner by 48 to 41 percentage points, although Republicans were quick to note that the poll surveyed registered voters, not likely voters.
Previous polls have found Udall and Gardner running neck and neck, with Udall typically a point or two ahead but within the margin of error.
The poll also found Democratic Gov. John Hickenlooper leading Republican Bob Beauprez in the gubernatorial contest by a margin of 49 to 43 percentage points. A Rasmussen Reports poll released shortly after the June 24 primary found the candidates tied at 44 percent.
Rothenberg’s decision to move the Senate race to “toss-up” comes nearly three months after the Cook Political Report did the same thing.
In his analysis in Roll Call, Rothenberg cited Gardner’s strengths as a candidate and fundraising ability as factors in his decision.
“Republican Rep. Cory Gardner is an excellent candidate, and his energy and sunny disposition will help make him broadly appealing,” said Rothenberg. “He had a strong fundraising quarter, ending June with $3.4 million in the bank.”
At the same time, Rothenberg noted that the Udall camp has pushed to “paint the challenger as out of touch on cultural issues, and he’ll have to keep the election’s focus on the jobs and the economy to win.”
“But Gardner may well be the best GOP challenger in the country, and we are moving the race to Tossup/Tilts Democrat, which better reflects the overall competitiveness of the contest,” said Rothenberg.
The Marist poll comes as something of an outlier, given the closeness of past polls, which Colorado Republicans chalked up to the survey’s methodology.
In addition to polling registered instead of likely voters, the survey includes “leaners”—those initially undecided who are pressed to make a decision—but doesn’t specify how many of those broke for Udall versus Gardner.
The Colorado Republican Party also pointed out that the Senate question immediately follows a job-approval question about Republicans in Congress, “which can prime the pump with responders and elicit an artificially negative opinion about Republican candidates.”
“The job approval of Democrats in Congress is not asked,” the Colorado GOP said in a statement.
Polling director Lee M. Miringoff noted in a statement that the poll wasn’t all good news for Udall, who continues to struggle with a favorability rating of 41 percent. His negative rating was 35 percent.
Udall did better than President Obama, who scored a 40 percent approval rating and 49 percent disapproval.
“Udall has the early advantage to hold his Senate seat,” said Miringoff. “But, he’s under 50 percent with a low favorability rating.”