Sen. John Ensign said it himself. It was going to be ugly if the Nevada Republican ran for re-election, no doubt about it.
Assuming he emerged the victor after a near certain primary challenge, which was a big if, there would have likely been a very nasty general election campaign.
Democrats, desperate to keep control of the Senate, had a lot to work with, given Ensign's well publicized extramarital affair with a political aide who was married to one of his staffers. Then there was the large payment from Ensign to the couple and a Senate ethics investigation, to boot.
So his announcement that he would not be seeking a third term made sense, especially since it was well known that other Capitol Hill Republicans preferred that Ensign just fade away. And so he will. Ensign said in a prepared statement:
"I have learned through the mistakes I have made that there are consequences to sin. I made a mistake. I owed up to the mistake. It was the biggest mistake of my life that I"ll regret for the rest of my life."
Rep. Dean Heller, is the Republican expected to keep the seat in GOP hands. A conservative who sometimes has voted against his party (he supported less restricted federal funding of embryonic stem cell research, for instance) his district is on the California border, on the other side of the state from Las Vegas and includes Reno, Carson City and Lake Tahoe.
Even though Heller's presence in the race would make it more likely than not that Republicans hang onto the seat Democrats, who had hoped the eminently beatable Ensign would be the candidate, struck a note of confidence.
A statement from Guy Cecil, executive director of the Democratic Senatorial Campaign Committee:
"Nevada is now an open seat, and ripe for a Democratic pickup. It remains high on our target list. Whoever Republicans field as their candidate will have a tough time holding onto this seat in a blue-trending state with President Obama at the top of the ticket. Democrats will have the resources needed to win this seat and just as important, will build a grassroots organization that matches 2008 and 2010."
Ensign is the eighth U.S. senator to announce he's not running for re-election, including four Democrats and one independent who caucuses with the Senate majority.