Congressional politics is defying all electoral norms these days. Usually, parties fear retirements more than anything and do as much as they can to get their representatives and senators to run again. Last week, however, Republicans breathed a small sigh of relief when Rep. Renzi announced he would not seek re-election in AZ-1. Stuck in ethical investigations, Renzi was playing right in the hands of the Democratic argument that Republicans are ethically challenged, and he could have doomed GOP chances in his district. Republicans learned the lesson of 2006, when they lost many of their House seats in heavy Republican territory because the incumbent was embroiled in scandals. (The worst were girlfriend-beating and mistress-strangling allegations made against Sweeney in NY-20 and Sherwood in PA-10). An open seat, Republicans reason, might actually be easier to defend.

The same thing is happening now: the resilience of Senator Craig, Senator Stevens of Alaska and Rep. Doolittle (CA-4) in the face of scandal are making their seats pick-up opportunies for Democrats. If any of these Republicans were to retire, Democratic chances would diminish.

Read full analysis - as well as an analysis of the South Dakota Senate race, where Republicans are also looking for a resignation to have any hope of having the seat - here, at Campaign Diaries.

• Idaho

Senator Craig is the only one I believe should not retire, given the shady nature of the police report and Republican hypocrisy. But it is undeniable that his running for re-election is what gives Democrats the best shot. Yesterday, Mitch McConnell talked to Craig and confirmed reports that Craig was going to fight to invalidate his own guilty plea -- and would stay in the Senate if he succeeded. McConnell implied he thought Craig should stay away from the Senate, and furious Republicans said the same, and moved to already replace Craig on the Senate committees he vacated last week.

But all might not be lost for Democrats even if Craig does resign. Idaho Governor Otter was reported yesterday to be considering appointing a place-holder, meaning someone who will not run for a full-term in 2008. Otter reportedly said that too many Republicans want the job, so that it would be unfair of him to act as a one-man Republican primary. In such a case, Otter would allow Lt. Gov Rish, Rep. Simpson and otehr Idaho Republican figures to fight it out in the primary, and then compete for an open seat. Republicans would probably still be favored, but La Rocco would at least have an opening.

• Alaska

Alaska Democrats have not been able to capitalize on opportunities the past few cycles, with former Governor Knowles losing a very tight Senate race in 2004 and a not-so-tight race for Governor in 2006. The Republican bench in Alaska is deep, and the Palin v. Knowles race 2006 indicated that the GOP has a huge edge in case of open seats. So, Dems have no chance against veteran Senator Stevens in 2008? Not so fast. We all remember how the FBI raided Stevens's house last month. Yesterday came news from The Hill that the allegations of unethical behavior are mounting against Stevens:

Sen. Ted Stevens has quietly steered millions of federal dollars to a sportfishing industry group founded by Bob Penney, a longtime friend who helped the Alaska Republican profit from a lucrative land deal, according to public records and officials from the state. Critics say those earmarked federal dollars could be the first example of how Stevens rewarded Penney for a land deal in Utah that reportedly earned the senator more than $125,000. Penney's group, for its part, rewarded Stevens with several expensive gifts at the time it was receiving the earmarked dollars.

With Anchorage Mayor Begich possibly getting in the race, Democrats would have an easier time making a case against Sen. Stevens than winning an open seat.

To finish off with the Senate, check out these Senate Rankings.

• CA-4

Rep. Doolittle represents a very Republican district of California that should be no trouble for Republicans. But he is being investigated for corruption and for his ties to convicted lobbyist Jack Abramoff. Plagued by the scandal, Doolittle barely survived in the 2006 election, edging Democrat Brown by a few points. Brown is back for a rematch, and knows that the Republican edge of the district would be to much to overcome if it wasn't for Doolittle's troubles. Yesterday, things got a bit more difficult for Doolittle, as two of his aides were subpoenaed to testify in front of a grand jury.

And then came out this poll from a Republican polling firm (Wilson Research Strategies) showing that Doolittle would lose against Charlie Brown 51% to 31%. Doolittle, who is facing a Republican primary against several candidates, would edge out his competitors with only 34% of the vote. You better believe Republicans are praying for Doolittle to resign or lose the primary. Or they might as well give up any hope of keeping CA-4 come November 2008.

Read full analysis - as well as an analysis of the South Dakota Senate race, where Republicans are also looking for a resignation to have any hope of having the seat - here, at Campaign Diaries.