The percentage of likely voters who would re-elect Ensign in 2012 sunk to 22 percent last week, an eight-point dip from August.

And among his core constituents, the decline is even more pronounced. Among Republicans, there was a 19 point decline from August with just 38 percent now stating they would vote to re-elect the junior senator.

The numbers are results from a poll of 500 registered Nevada voters surveyed by Mason-Dixon Polling & Research Inc. The poll has a margin of error of plus or minus 4.5 percentage points.

The results suggest Ensign has not been able to get voters to look beyond revelations of an affair with then-employee Cindy Hampton and allegations he lined up lobbying contacts for Doug Hampton, another former employee and Cindy Hampton's husband, to compensate for the infidelity.

News of the scandal broke in June but got a boost Oct. 2 with an article on the front page of The New York Times that detailed the lobbying allegations, using documents Doug Hampton provided to bolster his case.

"His numbers are still going down," said Mason-Dixon managing partner Brad Coker. "They are worse now than they have ever been. "I guess this drip, drip, drip is taking its toll."

According to the poll, 23 percent of respondents view Ensign favorably, 43 percent unfavorably, 32 percent were neutral and 2 percent didn't recognize him.

In August, 30 percent held a favorable view of Ensign, 37 percent unfavorable and 31 percent were neutral.

In May, before the affair became public, 53 percent viewed Ensign favorably, 18 percent unfavorably and 23 percent were neutral.

"It is clear he has taken a hit on it. The consistent barrage of negative news is bound to make an electoral difference," said Republican consultant Ryan Erwin. "It has all been negative news, and it certainly smells bad."

Since Ensign acknowledged the affair in June, he sought to move past it by asserting himself in the debate over health insurance reform.

This approach appeared to be working, as recent news coverage focused on amendments Ensign proposed for insurance reform bills but didn't note the scandal.

That changed with The New York Times item.

"Obviously this is a huge distraction," Erwin said, noting the lobbying violation allegations are unproven. "Instead of being innocent until proven guilty, politicians as a whole are guilty until proven innocent."

Jennifer Duffy of the Cook Political Report says eroding support among Republicans is the clearest sign Ensign's career hangs in the balance.

"That's not good. He has lost support within the family, as they say," Duffy said.

If the election were held today, 25 percent of Republicans said they would consider a candidate other than Ensign and 23 percent said they would vote to replace him. Both numbers are up from the August poll.

"You know he is going to get a primary challenge now," said David Damore, a political science professor at the University of Nevada, Las Vegas. "Even Nevada has its limits."

Contact reporter Benjamin Spillman at bspillman@reviewjournal.com or 702-477-3861.