Adding to the series of seven-figure donations boosting Senate Democrats’ war chest, Sen. Charles Schumer (D-N.Y.) cut a $1 million check Tuesday for his Caucus’ campaign committee, putting his contributions at the $2 million mark in just a few weeks.

Sitting on a campaign account that held almost $22 million a month ago, Schumer recently began cutting a series of large checks to the Democratic Senatorial Campaign Committee and a few state party committees culminating in Tuesday’s $1 million donation. The last check put him into a rough tie with Majority Whip Harry Reid (D-Nev.) for the single largest donation ever from a sitting Senator’s campaign account to one of the party committees.

His vigorous fundraising efforts on his own behalf and his increasing generosity as Election Day draws near has vaulted Schumer to the top of some insider’s lists to chair the DSCC in the 2006 cycle.

But Senators and key party strategists noted that Minority Leader Tom Daschle (D-S.D.), who is bogged down in his own furious re-election fight, has yet to have any talks with Schumer or a handful of other Democrats mentioned as potential chairman about the position.

Although he has said little about his plans, speculation about Schumer could become moot if he turns his attention homeward next cycle. Schumer and New York Attorney General Eliot Spitzer are already waging a behind the scenes campaign to get a leg up on becoming their party’s nominee for governor in 2006.

This has left the campaign committee, for the first time in recent cycles, without any obvious succession plan in place and prompted some insiders to openly speculate about whether a true freshman Democrat, such as state Sen. Barack Obama (Ill.), the overwhelming favorite to win an open seat on Nov. 2, could take the helm of the DSCC.

While a handful of Senators and several other sources confirmed the $1 million donation, Schumer declined to discuss his contributions or his own future.

“Our only focus is the election of 2004 — electing John Kerry president, getting a Democratic Senate, and re-electing Chuck Schumer to the Senate,” said Schumer spokesman Blake Zeff.

In the short run, the DSCC has benefited from a flurry of big checks from leftover or excess cash resting in several campaign accounts that could go a long way toward achieving financial parity with Republicans in as many as 10 states with critical races this year.

Schumer and Reid’s contributions came on the heels of a $3 million check from Kerry’s primary campaign account. Kerry had more than $50 million in leftover cash in August, money that he can’t use in the general election directly for his own benefit since he accepted public financing for the general.

A $1 million check from a legal compliance account from former Vice President Al Gore went to the DSCC earlier this summer, bringing the committee’s total haul to about $7 million from just four sources.

Democrats hope such largess will pump up energy levels in other donors to demonstrate how much they believe they have a chance at winning on Nov. 2.

“Anyone who thinks that this is not a real horse race is just not reading the positions [of the campaigns] right,” said Sen. Jon Corzine (N.J.), DSCC chairman.

Corzine, who is up for re-election in 2006 and therefore cannot remain chairman of the DSCC, declined to talk about who his successor might be.

That decision, like so many others in the Capitol, will very likely depend on the outcome of the elections on Nov. 2.

Most importantly, the Democratic leader is in charge of making the DSCC pick, and Daschle is in a neck-and-neck race with former Rep. John Thune (R-S.D.). A Thune victory would leave the slate of Democratic leadership up in the air, as Reid would likely run for leader and it remains unclear whether others would challenge him.

If Daschle wins re-election and there is no other leadership shuffle in the Caucus, aides said he would like to nail down the DSCC chairman by the time the lame duck session is over, likely to be some time before Thanksgiving.

But there have been past struggles to determine who would take over that panel, particularly in the mid-1990s when then-Sen. Bob Kerrey (D-Neb.) twice had to be coerced into taking the post.

While some think the DSCC job is Schumer’s for the taking, several other Senators have had their names floated for the position, though none are actively pursuing it. “It’s nothing that I desire to do,” said Sen. Evan Bayh (D-Ind.), noting that he has two young children.

“I don’t know what they would have to do to get me to take it. I’m not seeking it,” said Sen. Jack Reed (D-R.I.).

“Lord, I’ve got 28 days I’m focusing on right now. I’m not going there,” said Sen. Blanche Lincoln (D-Ark.), pointing to her re-election effort.

With Schumer possibly running for governor and no other obvious contender, some party insiders are pushing for Obama or possibly Erskine Bowles (D-N.C.) if he wins his Senate race. The DSCC has never had a true freshman as its chairman, so several strategists predicted that it would be more likely for Obama to become vice chairman of the committee.

But one senior strategist suggested either Obama — who became hugely popular among Democrats after his convention speech — or Bowles — a former White House chief of staff with ties to many donors — could take on the chairmanship immediately.

Even before officially winning his Senate seat, Obama has become a financial draw for the DSCC and other Democratic candidates. On Monday, at a campaign stop in Quad Cities, Obama headlined a fundraiser benefiting Iowa state Senate and House candidates.

And this week he sent out his second direct mail/e-mail pitch on behalf of the DSCC, this one called “Fighting for 51.”

“It’s about rolling up our sleeves and working for the next 28 days to elect Democratic candidates from Alaska to Florida — candidates who share our vision and our abiding faith in the possibilities of this nation,” Obama wrote.

His campaign declined to comment on speculation about leadership aspirations.