Rep. Joe Crowley (D- N.Y.) has a big decision to make.

With Rep. Ellen Tauscher (Calif.) packing up for a State Department gig, the ambitious New Yorker has a clear path to replace her atop the New Democrat Coalition, the bloc of pro-business moderates emerging as a force in the 111th Congress.

But leading the New Democrats is likely to occasionally put Crowley at odds with the House Democratic leadership and could compromise his goal of one day climbing the House Democratic ladder. Crowley has wanted to serve in the Democratic Caucus hierarchy for sometime, and he ran unsuccessfully for Caucus vice chairman in 2006.

“The decision Joe has to make is whether he wants to stay on the leadership track,— said Rep. Ron Kind (Wis.), who like Crowley is a New Democrat vice chairman and a possible Tauscher successor. “If you want to be in leadership, it’s not necessarily helpful to be the chair of the New Dems.—

Tauscher has been a moderate force in the House Democratic Caucus for several years and has led the New Democrat Coalition since 2005 — a period of tremendous growth for party centrists. President Barack Obama plans to tap Tauscher to serve as undersecretary for arms control and international security at the State Department.

At stake with her departure is the leadership of a group that has quickly established itself as a Democratic powerhouse.

A former Wall Street investment banker, Tauscher spent the past four years helping to reinvigorate the New Democrats. She spearheaded a moderate vote last month against a mortgage measure that forced Democratic leaders to delay its consideration and then grant concessions. Obama declared himself a New Democrat in a huddle with the caucus earlier this month, and White House Chief of Staff and former Rep. Rahm Emanuel (Ill.) used to belong.

The New Democrats formed in 1997, aligning closely with the Bill Clinton White House and enjoying influence there for the twilight of his presidency. But during the George W. Bush years, with Republicans dominant on Capitol Hill, the group wandered into obscurity. Tauscher helped revive it, pruning its membership of casual members, kicking off a political action committee and refocusing the group on trade and technology initiatives.

While lawmakers, aides and strategists close to the group pointed to its deep bench as evidence it will continue to thrive after Tauscher, they were also bracing for her exit. “There isn’t any Ellen Tauscher within the New Dems,— Rep. Artur Davis (D-Ala.) said, pointing to her “inside game— working with lawmakers of both parties and her “outside game— as a saleswoman for the group’s priorities on television.

If Crowley opts against a bid to replace her, Rep. Melissa Bean (Ill.) is widely thought to be next in line, numerous sources close to the group said. But two others already in the group’s leadership left the door open for bids: Kind and Rep. Allyson Schwartz (Pa.), a third-term lawmaker thought to lean further left than most in the group, a factor that could complicate her ascension.

Less than a day after the Tauscher news broke, Crowley is still mulling his options.

“I’m flattered that many of my colleagues think I have what it takes to lead this caucus forward,— he said.

Crowley may have reason for pause. Stung by his failed 2006 leadership campaign, the New Yorker resisted moderates’ efforts late last year to draft him into another race against contenders favored by Speaker Nancy Pelosi (Calif.). But once newly elected Caucus Vice Chairman Xavier Becerra (Calif.) appeared headed to the White House to become Obama’s trade negotiator, Crowley jumped at the chance to replace him in leadership, forming a whip team and lapping the field of potential challengers by lining up significant support. Becerra ended up withdrawing from consideration, once again ending Crowley’s hopes of a leadership slot.

Crowley may have some time to decide his latest move, however. Tauscher is telling colleagues the Senate confirmation process for her new post could take up to eight weeks. And several sources said Crowley has a deep enough well of support that other contenders will wait to see what he decides before making their intentions clear.

Another factor in Crowley’s decision: He is already stretched thin with assignments. He recently agreed to head up fundraising for the Democratic Congressional Campaign Committee in addition to serving as a Chief Deputy Whip, sitting on the Ways and Means Committee and chairing the Queens County Democratic Committee.

Also, Tauscher has not yet been formally nominated for the post, and even seemingly airtight executive branch appointments for lawmakers can fall apart.

As speculation under the Dome focused over the New Democrats’ future, talk in California’s East Bay centered on Tauscher’s prospective House successors. Emerging is a quartet of current or former state lawmakers, all of whom are Democrats: Assemblyman Tom Torlakson, Assemblywoman Joan Buchanan, state Sen. Mark DeSaulnier and former Assemblyman Joe Canciamilla.

“Look at any of the Democratic legislators within [the 10th district] or within a spitting distance of that district,— said Allan Hoffenblum, publisher of the California Target Book, a political tip sheet.

All four are veteran officeholders who worked their way up from local government to county government before serving in Sacramento. Of the group, Torlakson is probably the best known. He defeated George Miller IV, the son of Rep. George Miller (D-Calif.) in a high-profile Assembly primary in 1996.

But to run for Congress, Torlakson would have to change course: He’s already preparing to run for state superintendent of public instruction in 2010 and has planned his formal campaign kickoff for April 3.

Torlakson and DeSaulnier are political allies — in fact, given California’s term-limit laws, they’ve played musical chairs with their Assembly and Senate seats — so they are unlikely to run against each other.

But Canciamilla is another story, and he’s the only one of the candidates who wouldn’t be decidedly to Tauscher’s left.

During his legislative tenure, he angered party bosses and labor leaders by forming a caucus of moderate Democrats and working with Republicans on health care legislation.

Canciamilla also has been thinking about 2010 and has created an exploratory committee in advance of a possible run for state attorney general.

Because Tauscher must go through a confirmation process, she probably won’t leave Congress in time for a special election to be scheduled to coincide with a statewide special election on budget and tax matters set for May 19.

Under California law, there will be an all-party primary for the special Congressional election. If no candidate tops 50 percent of the vote, the top vote-getters in each party advance to a special general election.

The 10th district, which takes in a major portion of Contra Costa County in the East Bay, is heavily Democratic — Democrats have a 47 percent to 29 percent edge in voter enrollment over Republicans — so the GOP is not expected to be a player in the special election.

“There will be a nice family feud on the Democratic side,— Hoffenblum predicted.