For all the recent focus on Idaho Sen. Larry Craig’s future, the more significant political developments were the announced retirements of Virginia Sen. John Warner and Nebraska Sen. Chuck Hagel.

Craig’s possible departure probably won’t change the landscape much since his appointed successor and next year’s elected one are both likely to be Republicans.

But the other two retirements increase the probability that Democrats will not only keep the Senate next year but also add to their tenuous 51-49 majority.

More important, it now seems possible that the next president will face close to a filibuster-proof 60-senator coalition of Democrats and moderate Republicans.

That could give a Democratic president a virtual working majority, at least on domestic issues, assuming that president reached some across party lines. It could also hamper a Republican president with a conservative agenda.

Besides, the next president will likely have a Democratic House.

Next year’s Senate races were always going to be tough for the GOP, with 22 Republican seats up for election and just 12 Democratic ones. But in recent weeks the numbers have gotten worse.

In Virginia, John Warner’s decision to retire opens the way for former Democratic Gov. Mark Warner (no relation). A moderate-to-conservative Democrat who ended his term as governor with high approval ratings, the younger Mark Warner had considered a presidential bid but bowed out, citing family concerns.

He is expected to announce that he will run for the Senate, where he’ll be the early favorite.

Two Republicans are considering the race: Rep. Tom Davis, a savvy moderate from northern Virginia, and former Gov. James Gilmore, a conservative who briefly ran for president and had a mediocre gubernatorial record.

The Virginia GOP has yet to decide whether to have a convention, which might favor Gilmore, or a primary, which would probably favor Davis. But either will find Mark Warner a formidable rival in a politically evolving state that last year elected Democrat Jim Webb to its other Senate seat.

In Nebraska, Democratic hopes depend on whether Bob Kerrey, a former governor and senator, decides to run. He is president of the New School University in New York. Otherwise, the seat will probably stay Republican.

The fourth open GOP seat is in Colorado, another state in which Democrats have recently shown strength. Democratic Rep. Mark Udall, a son of the late Arizona Rep. Morris Udall of Arizona, is the early favorite over former Rep. Bob Schaffer, a Republican.

But that’s not the end of potential GOP problems.

In New Hampshire, where freshman Republican John Sununu edged out former Democratic Gov. Jeanne Shaheen in 2002, polls show her with a big lead in a potential rematch. She has not yet decided whether to run.

In the West, the two most senior Republicans have problems.

A corruption probe is looking at how Sen. Ted Stevens of Alaska steered federal funds to contributors. In New Mexico, Sen. Pete Domenici reportedly pressured a U.S. attorney to step up an investigation of alleged Democratic corruption.

Three other younger, more moderate Republicans could face difficulty in states that have tended to vote Democratic in recent elections, Sens. Susan Collins of Maine, Norm Coleman of Minnesota and Gordon Smith of Oregon. Early polls show all three ahead.

The remaining 13 GOP seats seem safe, though Democrats claim that several others may be vulnerable, including Sen. John Cornyn of Texas. But it looks as if only a national Democratic tidal wave would endanger them.

Meanwhile, only two Democrats seem to be in any jeopardy. In Louisiana, state Treasurer John Kennedy switched to the GOP to challenge Sen. Mary Landrieu, who may suffer from a post-Hurricane Katrina decline in the state’s black population.

But in South Dakota, Democrat Tim Johnson’s return to the Senate after nine months away due to a stroke has buoyed Democratic hopes that he can hold his seat.

The presidential race could influence some races. Some Democrats worry that congressional candidates may suffer in conservative states if Sen. Hillary Rodham Clinton is their presidential nominee.

But some Republicans think a greater likelihood is that their party will suffer from continuing negative fallout over the Iraq war.