The Democratic National Convention in Charlotte, N.C., is mainly about reelecting Barack Obama. But Obama’s party also is defending 23 Senate seats this November (compared to the GOP’s mere 10), and there’s a fair chance that next January, even if he wins, President Obama would be bedeviled by a Republican-run Senate far less inclined to cooperate than it was during the past four years.

“I think there’s a fifty-fifty shot that either one of us will hold or obtain the majority,” Guy Cecil, executive director of the Democratic Senatorial Campaign Committee, said during a briefing Tuesday on the 2012 election cycle’s hottest races.

Not very comfortable odds.

But Cecil, who pointed out that unlike in the 2006 and 2010 cycles, neither party “has the wind at its back,” held out the vague possibility that the Dems could “pick up one or two Republican seats.” This, even though Republican candidates and superPACs are collectively outspending them by a wide margin.

The Democrats currently hold a working majority of 53 seats (51 plus two independent senators, Joe Lieberman of Connecticut and Bernie Sanders of Vermont, who caucus with the party). Cecil refused to guess how many of those seats the Dems will keep. “I’m not big on predictions,” he demurred.

Sixteen Democratic incumbents are up this year, and Cecil listed Sherrod Brown of Ohio, Jon Tester of Montana, and Claire McCaskill of Missouri (still benefiting from the Todd Akin “legitimate rape” meltdown as competitively positioned, but by no means assured of victory. Akin was running 10 points ahead of McCaskill, widely considered the Dems’ most vulnerable incumbent, before he claimed in a television interview last month that women who are raped don’t get pregnant because “the female body has ways to try to shut that whole thing down.” The remark prompted the Republican establishment, including Mitt Romney and Paul Ryan, to demand that he drop out, and suddenly McCaskill found herself in the lead.

These days they are running nearly even.

“No question that Todd Akin provided a slight opening,” Cecil cautioned, “but I’m hesitant to believe any poll that shows a 20-point swing in a span of four days ... We are preparing for Todd Akin to stay in the race … Claire is running a good race in a red state against tough odds.”

Cecil sounded more sanguine about Florida Sen. Bill Nelson, who was running nearly 10 points ahead of challenger Connie Mack after Republican superPACs and Mack’s campaign spent $13 million against him.

In Indiana, Cecil was hopeful that Rep. Joe Donnelly will defeat Tea Party Republican Richard Mourdock, who knocked off six-term moderate Dick Lugar in a nasty primary race. Among the open-seat races, Cecil said he expects that in Connecticut, Rep. Chris Murphy will defeat second-time candidate and professional wrestling mogul Linda McMahon, who spent nearly $50 million to lose in 2010—a year that overwhelmingly favored her fellow Republicans. He said former Virginia Gov. Tim Kaine, running against former Sen. George Allen, will probably run ahead of Obama in the state and beat Allen by a close margin. He also touted the prospects of Heidi Heitkamp in North Dakota, a state where Obama is losing by double digits. And although many political prognosticators have declared former Nebraska Sen. Bob Kerrey’s attempt to return DOA, Cecil disagreed.

“No question Nebraska is a Republican state, but we’ve seen the margin close and Deb Fischer [Kerrey’s opponent] is leading by single digits.” After retiring from the Senate in 2000, Kerrey spent the last decade living in Manhattan as president of the New School. “Bob Kerrey is a unique candidate and has been successful in winning elections for governor and senator. He’s reintroducing himself to voters. We don’t think it’s over.”