Udall has led in six straight polls. All between 2 and 6 percent leads.
The latest poll has shown Obama's approval numbers in Colorado at 39%. He has been doing a few points better nationwide. Polls taken throughout 2014 have shown Obama's approval numbers in Colorado below the national average.
Obamacare hasn't polled well in Colorado either. A Rasmussen poll found support for Obamacare at only 39%. When Rasmussen did a nationwide poll it showed 44% supported Obamacare. A quinnipiac poll taken a few months ago had shown support at 37% in CO while nationwide it was at 41%.
Recent hypothetical polls have shown Republican challengers with small leads over Hillary Clinton. This in spite of the fact that she leads those same challengers by about 10% in nationwide polling. Clearly Clinton is dragged down by Obama, Obamacare, and the fact that she is an older candidate in a state that has a lot of younger voters.
These results are interesting because Colorado has shown itself to be slightly more liberal than the nation as a whole in the last two presidential elections. The RD Index shows 1.5% pro Dem 2012 and 1.8% pro Dem in 2008.
Why has Udall been able to stay on top in the polls?
One reason could be finances. As of June 30, Udall out spent Gardner 7.9 million to 1.9 million and still had 2.4 million more cash on hand.