This was to be the great coming together of Democratic leaders and party organizations that had been promised throughout the bitter presidential primary battle between Sens. Barack Obama (Ill.) and Hillary Rodham Clinton (N.Y.).

“Today we stand united as a party, focused on putting an end to the idea of a third Bush term,” Democratic National Committee Chairman Howard Dean said Tuesday at a gathering of officials from the House and Senate leadership, the Democratic Congressional Campaign Committee, the Democratic Senatorial Campaign Committee, the Democratic Governors Association and Congressional supporters of both Obama and Clinton.

Most of the Democratic statements, including that of Speaker Nancy Pelosi (Calif.) tended to follow the same pattern: acknowledging the leadership of Clinton during her campaign, emphasizing the party is now firmly behind Obama and promoting the theme that a victory by Sen. John McCain (R-Ariz.) in the fall would be another four years of President Bush’s policies.

But Dean and Pelosi also touched on what an Obama candidacy will mean to downballot races around the country, a subject that has become especially important to Congressional candidates in districts and states where Clinton proved she was the strongest candidate during the primary season.

“Barack Obama is a candidate that will go anywhere in America and help our ticket,” Dean said. “Sen. Obama has said he wants to run a 50-state campaign, and we’re ready for that at the DNC.”

Dean appeared to be taking a shot at Congressional Democrats who in the 2006 cycle questioned his commitment to devote resources to states where the party is traditionally outgunned by the GOP.

But in some districts where Democrats are trying to run as conservatives, the presence of Obama at the top of the ticket could do more harm than good.

That line of thinking was certainly at play in the special election campaign in northern Mississippi’s 1st district last month. In that hotly contested race, now-Rep. Travis Childers (D) went on the air late in the campaign to emphatically state that he had never even met Obama after his Republican opponent played up Childers’ ties to the Illinois Senator. The seat is expected to be competitive again in the fall.

Meanwhile, Republicans are already looking for ways to exploit Obama’s candidacy in districts where they think his presence will hurt the Democratic candidate.

The National Republican Congressional Committee sent out a news release Tuesday expressing its “surprise” that Rep. Jim Marshall (D), who represents the battleground 8th district of Georgia, has not said whether he will endorse Obama.

“Despite his politically motivated efforts to run away from the Democratic presidential nominee, Jim Marshall seems to be reading off the same song sheet when it comes to massive tax hikes, government-run health care and defending our homeland,” NRCC spokesman Ken Spain said.

Marshall’s opponent, Air Force Maj. Gen. Rick Goddard (R), has made a point to bring up the Obama-Marshall ballot in interviews with Washington, D.C., newspapers this week. Goddard has been on Capitol Hill visiting GOP leaders and he attended the Republican Conference meeting Tuesday.

In places like Kentucky, where Clinton won overwhelmingly in last month’s primary, some Democrats say an all-out 50-state strategy for Obama might backfire on certain Democratic candidates.

One Kentucky Democratic operative said this week that it would be a surprise if Obama made more than one campaign stop in the Bluegrass State this fall. And even that, the operative said, would probably be in Louisville so that Democrats in the rural parts of the state can keep their distance from a candidate who hasn’t proven to be as popular in rural, blue-collar areas.

But Democrats say that just as party leaders have come together solidly behind Obama, so too will voters, for whom change is the key to this election.

“Whether it’s our national security or our economic security, we do not need four more years of George Bush,” Pelosi said. “Women and blue-collar workers have the most to gain by the election of Barack Obama as president of the United States and the most to lose by the election of John McCain.”