Republican Cory Gardner has opened up a four-point lead in a Colorado Senate race that 's key in determining whether Democrats can hold onto their majority , a new CNN/ORC poll shows . Gardner held a 50 percent to 46 percent edge on first-term Democratic Sen. Mark Udall in the survey of 665 likely voters , conducted Oct. 9-13 . The poll 's margin of error is plus or minus 4 percentage points . Republicans have targeted Udall and several other Democratic incumbents in their effort to win at least six seats this fall -- enough to gain a Senate majority for President Barack Obama 's final two years in office . Traditional Democratic advantages among women and urban voters are n't enough to overcome strong headwinds , said CNN Polling Director Keating Holland . `` Udall is getting clobbered in the all-important suburbs , as well as in rural areas , and his lead in Colorado cities is not enough to overcome that , '' Holland said . `` There is a gender gap , but in this case it appears to be working in favor of the Republican . Udall has a nine-point advantage among women , but that is dwarfed by the 20-point lead Gardner has among men , '' he said . Hurting Udall is an underwater favorability rating of 45 percent -- with 51 percent of those surveyed saying they have an unfavorable opinion of the Democrat . Gardner , meanwhile , is viewed favorably by 50 percent of likely voters , with just 42 percent saying their opinion of him is unfavorable . Colorado 's governor 's race is even closer . Incumbent Democratic Gov . John Hickenlooper is backed by 49 percent of likely voters , while Republican challenger Bob Beauprez has 48 percent support , the CNN/ORC poll found . The Democratic incumbents are both outperforming Obama , who twice won the state 's nine electoral votes but now has an approval rating of just 39 percent in Colorado , while 59 percent of likely voters say they disapprove of the job he 's doing .
A CNN/ORC poll finds Republican Cory Gardner is leading Democratic Sen. Mark Udall , 50-46 . The poll, conducted from June 30 to July 1, shows that the two senators are locked in a statistical tie among likely voters with just over half of those polled saying they would vote for either candidate. Udall is one of a handful of Democratic incumbents that Republicans have targeted this year .