According to Senator Tom Harkin (D-Labor), the Senate may vote next month on a Card Check compromise:

Sen. Tom Harkin (D-Iowa) indicated Wednesday that he will be ready to bring up the long-stalled Employee Free Choice Act next month, following weeks of negotiations with key stakeholders.

“We’re in meetings right now. I’m still hopeful that we can get something done,” Harkin said.

The Iowa Democrat has regularly huddled with Democratic Sens. Mark Pryor (Ark.), Charles Schumer (N.Y.) and Arlen Specter (Pa.) to try to hatch a compromise on the measure, known as “card check.” On Tuesday, Harkin included AFL-CIO legislative director Bill Samuel in the talks—an indication that progress is being made.

Excluded from the closed-door talks have been Democratic naysayers to the bill such as Sens. Ben Nelson (Neb.) and Dianne Feinstein (Calif.), whose support Harkin will need to avoid a filibuster…

Specter is seen as key to any agreement. Before he defected to the Democratic Party in late April, he took to the floor to oppose the legislation in its current form. Since then, he has softened his tone, but he has repeatedly said he will oppose any proposal that includes the open-ballot rule.

When asked if the labor industry would agree to any measure that does not include that provision, Harkin seemed uncertain, saying it’s one “of about three problems I have right now.”

Harkin said he hopes to push the legislation to the floor next month, but that he won’t take any action unless and until Minnesota Democrat Al Franken is sworn in as a Senator. Franken would give Democrats 60 votes, enough to avert a filibuster.

There’s a lot to take note of here. The first thing is the value of a contested primary. Arlen Specter opposed Card Check when he was thinking about a Republican primary and a general election. Now you can expect him to do whatever it takes to get the blessing of the unions as he heads for a tough primary against Joe Sestak (D-PA). Polls show Specter is vulnerable to a real Democrat; he may need the foot soldiers the unions bring, and it’s likely that whatever his public posture, he’s working behind the scenes to deliver for labor.

I’m also surprised to see Mark Pryor apparently emerging as a key voice for Card Check. One of the biggest opponents of the measure is WalMart - which is based in Pryor’s home state. If Pryor is an advocate for Card Check, it might come back to haunt Blanche Lincoln - who is up for re-election next year. If Card Check passes thanks to Pryor, it could make WalMart executives more willing to push back against the Democrats who passed it.

The next thing that stands out is the changed view of the 2010 elections. A few months ago, Democrats spoke confidently of adding to their Senate margin. If they genuinely expected to gain even one seat, they would probably not be so eager to surrender key parts of the Card Check bill in a rushed compromise. If they really expected to get to 61 or 62 seats, they would be less eager to give in.

This points to the next item: why the rush? Contentious bills normally wait until after ‘must-passes’ get done. Congressional Democrats have health care and cap-and-tax as top priorities; why is Card Check suddenly moved to the front of the line? Leaders know that any Senator who takes a tough vote for Card Check will have more latitude when it’s time for votes on health reform and energy taxes. Why are they risking top Obama priorities to deliver for Labor?

The likely reason is health - or the lack of it. Assuming that Al Franken is eventually seated to replace Norm Coleman, Democrats will hold 60 Senate seats. They need every one of those votes to break a filibuster of Card Check, and Ted Kennedy has only voted 7 times this year - the last on April 27. The last time Bob Byrd voted was on May 13. Harkin, Reid, the unions, and the Democrats, will need those two - and all 58 others - to appear in the Senate chamber to vote, in order to pass Card Check. That’s going to be a challenge. Given the frailty of their majority, they want this vote to come as soon as possible.