As part of a strategy to expand their threadbare Senate majority, Democrats are moving to target usually impenetrable Republican seats, hoping to keep Republicans on the defensive and boost the party’s prospects for ousting vulnerable GOP incumbents next year.

The Democratic Senatorial Campaign Committee is prepared to sink money and manpower into solid Republican states across the South and elsewhere. But the DSCC’s plan depends on three factors not guaranteed to materialize: continued political peril for Republicans deep into 2008, the retirement of GOP incumbents in solid Republican states and the recruitment of stellar Democratic candidates in places where they often are in short supply.

“It’s too early to say how many of these states will have serious races. But the goal is to put as many of them into play as possible,” said one Democratic strategist familiar with the DSCC’s thinking. “The more states you play offense in, the more states you move into the first tier and the more chances you have to win.”

Those Republican Senate seats considered in the first tier of potential Democratic pickups are well-known. They include incumbent seats in Maine, Minnesota, New Hampshire and Oregon, as well as an open Colorado seat.

However, the DSCC also is focused on threatening two additional tiers of Republican seats, both of which are made up of seats that are in GOP strongholds where Republicans tend to have the advantage — especially in presidential cycles. The first includes Kansas, Kentucky, North Carolina, Oklahoma and Texas; the second includes Idaho, Mississippi, Nebraska, New Mexico and Virginia.

Republicans say this is a fine strategy — for the previous cycle.

Precisely because 2008 is a presidential as opposed to a midterm cycle, Republicans say red states likely will perform much closer — if not completely — to type, even if President Bush’s poll numbers continue to sag.

Not only will having the presidential nominee at the top of the ticket energize GOP and like-minded voters to vote the Republican ticket, but so will nearly two years of a Democratic-controlled Congress, which Republicans say already is overreaching too far to the left.

Additionally, Republicans say, 2008 is likely to be dominated by the presidential nominees, preventing the DSCC from hanging Bush around the necks of GOP candidates as it did successfully last year.

“The presidential race will take the current president out of the race a bit and put the Republican nominee in play, which will benefit us,” said one Republican operative based in Washington, D.C.

Added another D.C.-based GOP strategist: “It’s going to be tough for Democrats to go into red states and try and be competitive, given what we’ve seen from them [legislatively] in their first 100 days.”

Democrats disagree.

They believe the Iraq War still could be an albatross for the GOP in 2008 and provide their candidates with a shot at winning Senate races in usually solid Republican states.

In the first group of states the DSCC is hoping to play in — Kansas, Kentucky, North Carolina, Oklahoma and Texas — the incumbent Republicans all are planning to run for re-election.

The political performance of each state over the past generation suggests the GOP should be in good shape. But the DSCC feels that if it can recruit the right candidate, Democrats could be in a position to pull off an upset — especially if one of the Republicans commits one or more serious campaign errors at some point in the race, similar to then-Sen. George Allen’s (R-Va.) “macaca” moment in his losing contest with now-Sen. Jim Webb (D-Va.).

In the second group — Idaho, Mississippi, Nebraska, New Mexico and Virginia — the Republican incumbents up for re-election have yet to solidify their 2008 plans, although Sen. Thad Cochran (R-Miss.) has indicated he intends to run.

The DSCC sees opportunities in these states if the incumbent retires — particularly in New Mexico and Virginia, which are competitive but would be tough for Democrats to crack with icons such as GOP Sens. Pete Domenici (N.M.) and John Warner (Va.) on the ballot.

In Virginia, Democrats hope to convince the popular former Gov. Mark Warner (D) to run if Sen. Warner retires. Democrats also believe they may be able to recruit New Mexico Gov. Bill Richardson (D) or Rep. Tom Udall (D) to run if Domenici opts against a seventh term.

“Retirements are obviously key. Any seat is easier to take if it doesn’t have an incumbent in it,” said Brad Woodhouse, executive director of the liberal group Americans United for Change and a former DSCC staffer. “An open seat attracts better candidates, and better candidates are in a stronger position to raise their own money, so retirements are huge.”

The DSCC thus far has failed to recruit a top-flight candidate to challenge Sen. Gordon Smith (R) in Democratic-leaning Oregon, suggesting it might be difficult for the committee to find individuals capable of threatening Republicans in GOP states with a thin Democratic bench.

Case in point is Idaho, which Democrats feel could be worth targeting if Sen. Larry Craig (R) retires. Despite Democrats’ optimism about their possibilities there, former Rep. Larry LaRocco is the only Democratic Senate candidate on the horizon in the Gem State, and his already-announced 2008 bid comes on the heels of a 20-point drubbing in his 2006 race for lieutenant governor.

Lt. Gov. Jim Risch (R), a former acting governor who beat LaRocco last year, has indicated he’ll run for Senate if Craig retires.

The DSCC’s potential recruiting difficulties also are evident in Alaska, Georgia, South Carolina, Tennessee and Wyoming. Democrats at this point do not envision being able to compete for those Senate seats in 2008, even though a few of those states have shown a penchant for electing Democrats to statewide office (both Tennessee and Wyoming have Democratic governors).

DSCC officials do have potentially formidable candidates in mind in several of the red states they are targeting. The key to the committee’s approach to creating competitive races in these states could revolve around its ability to lure top-flight recruits into the race.

In Kansas, Democrats are eying Joe Hoagland (D), who before switching parties was the Republican Majority Leader of the state House of Representatives. With Democrats’ recent success in Kansas at the gubernatorial and Congressional level, the DSCC feels there could be an opportunity despite the fact that Sen. Pat Roberts (R) remains popular.

In Kentucky, Democrats are talking about businessman Charlie Owen (D) to challenge Senate Minority Leader Mitch McConnell (R), while in Mississippi they’re high on former state Attorney General Mike Moore (D). Moore led the legal fight waged by several states against the tobacco industry and helped negotiate a payout worth millions of dollars to several states.

In North Carolina, state Attorney General Roy Cooper (D) is a favorite of Democrats to take on Sen. Elizabeth Dole (R). Rep. Brad Miller (D) is floating his own name and is considered credible because he is a sitting Congressman. In Nebraska, Omaha Mayor Mike Fahey (D) has indicated he would be inclined to run if Sen. Chuck Hagel (R) retires.

In Oklahoma, Democrats are examining state Sen. Andrew Rice (D) and state Attorney General Drew Edmondson (D), who has been elected to four consecutive terms, as possible challengers to Sen. James Inhofe (R). In Texas, Democrats are talking up about a half-dozen individuals to challenge Sen. John Cornyn (R), including Rep. Nick Lampson (D) and wealthy San Antonio trial attorney Mikal Watts (D).

“By fielding strong challengers, you put yourself in a position to win if the national environment stays bad for Republicans,” the Democratic strategist familiar with the DSCC’s thinking said. “We won’t end up with a strong challenger in every Republican state, but that’s the goal.”

Even before issues of incumbent retirements, political environment and candidate recruitment are accounted for, the DSCC begins the cycle with a natural advantage over the National Republican Senatorial Committee.

Not only did the DSCC take a nearly 2-1 fundraising lead over the NRSC in the first quarter of this year, but there are 21 GOP-held seats up in 2008, compared with just 12 for the Democrats.

Although the two committees are roughly equal in cash on hand thanks to the DSCC’s existing debt and there is no guarantee Senate Democrats will maintain their fundraising advantage, the DSCC is aiming to exploit the fact that it has almost half as many seats to defend as the Republicans to put several otherwise safe GOP seats in play.

NRSC spokeswoman Rebecca Fisher acknowledged the difficulty of having to defend nearly twice as many seats as does the DSCC. But she said the NRSC is confident because its vulnerable incumbents are prepared, adding that “our offensive position is better.”

“The states that we’re playing offense in,” Fisher said, such as Arkansas, Louisiana and Montana, are politically more inclined to flip than are the GOP seats that the DSCC is targeting.

But Republicans, who need to pick up two seats to regain control of the Senate, have not lured any candidates into those races yet, and at this point the only incumbent in the three states that the DSCC is even remotely worried about is Sen. Mary Landrieu (D-La.).