Democratic incumbent Mark Udall and Republican challenger Cory Gardner are locked in a statistical dead heat in the Colorado race for U.S. Senate, according to the latest Suffolk University/USA TODAY poll.

The poll of likely voters in the general election shows Gardner backed by 43 percent and Udall by 42 percent, a difference that is well within the poll’s 4.4 percent margin of error. Another 10 percent of likely voters remain undecided, and four independent and third-party candidates were in low single digits.

The Colorado race for governor also is neck-and-neck, with 43 percent of respondents supporting Democratic incumbent John Hickenlooper and 41 percent backing Republican Bob Beauprez, a former congressman, with 10 percent of likely voters undecided. This race also had four additional candidates in single digits.

The Obama factor

Of those polled, 55 percent have an unfavorable opinion of President Barack Obama, while 43 percent have a favorable view. More than 56 percent disapprove of Obama’s job performance, while nearly 42 percent approve.

“The president’s favorability and job approval continue to struggle, mirroring what we are seeing in other states,” said David Paleologos, director of the Suffolk University Political Research Center in Boston. “Obama’s falling out of favor appears to be taking its toll on Democratic candidates.”

Concerns about national security and terrorism are taking center stage. While voters said jobs (24 percent) was the No. 1 issue as the midterm congressional elections approach, security and terrorism was second (17 percent), ahead of the federal budget deficit, health care, immigration and education. Nearly half of likely voters (49 percent) feel the economy has improved over the past two years, while 29 percent say it’s stayed the same, and 19 percent say it’s gotten worse.

Marijuana doubts

Colorado voters may be having second thoughts about the legalization of marijuana. A slight majority of voters (50.2 percent) say they do not agree with the decision to legalize recreational marijuana in that state—a decision made by voters in 2012--while 46 percent continue to support the decision. Nearly 49 percent do not approve of how the state is managing legalized pot, compared to 42 percent who approve.

“Although it's a close split overall, opposition comes mainly from women statewide who oppose it fifty-six percent to forty-one percent and additional pushback from voters over fifty-five years of age,” Paleologos said. “This is offset by younger voters between eighteen and forty-five who still support it by a twenty-point margin.”

Senate race by region

The Suffolk University/USA TODAY poll shows Udall leading in the Denver/Boulder area by a 22-point margin, but tied or losing everywhere else. Gardner was ahead in the eastern/rural area by 18 points due to overlap with the Fourth Congressional District, which he currently represents.

2016 presidential forecast

Looking ahead to the 2016 presidential elections, Kentucky Sen. Rand Paul (12 percent) led the Republican pack, followed by Wisconsin Congressman Paul Ryan (10 percent), and former Arkansas Gov. Mike Huckabee, New Jersey Gov. Chris Christie and Wisconsin Gov. Scott Walker at 8 percent each. However, 16 percent of voters were undecided. When asked about a second choice, Huckabee led at 12 percent, with 12 other candidates in single digits.

The wild card in Colorado, as in other states polled, is Mitt Romney, who would be the choice of 35 percent of likely Republican voters if he were to enter the fray. Paul’s share decreased to 10 percent, with all other candidates—and undecideds--in single digits.

Former Secretary of State Hillary Clinton continues to dominate the Democratic contest, with 59 percent of Democratic voters supporting her as their first choice in the primary. U.S. Sen. Elizabeth Warren of Massachusetts showed greater strength in Colorado than elsewhere, with 21 percent, and Vice-President Joe Biden was a distant third at 8 percent. Six percent were undecided.

Methodology

The Suffolk University/USA TODAY survey was conducted via landline and cell phone. All respondents indicated that they were very or somewhat likely to vote in the Nov. 4 election. The field of 500 likely general-election voters was conducted Saturday, Sept. 13, through Tuesday, Sept. 16. The margin of error is +/-4.4 percent at a 95 percent level of confidence. Results are posted on the Suffolk University Political Research Center website. For more information, contact David Paleologos at 781-290-9310.