After many setbacks, the “card check” bill’s chief Senate sponsor is expressing new optimism that the legislation, which would ease union organizing, could be on the Senate floor this summer.

In recent weeks, Tom Harkin , D-Iowa, has been meeting with a small number of senators, with occasional input from Majority Leader Harry Reid , D-Nev., to hash out alternatives to the legislation (S 560, HR 1409) that would still reflect its basic purpose: making it easier for workers to certify and join viable unions.

Compromise has been on the agenda since the legislation was introduced in March, but strategies have changed in recent weeks, as getting 60 votes in the Senate has evolved from exploring common principles to examining what can be excised in order to bring the bill to the floor — even if that means taking the “card check” out of card check.

Much of the effort centers on Arlen Specter , D-Pa., who has discussed the bill with Harkin since switching political parties in April.

Publicly, Specter has remained open to supporting some form of the legislation, but has insisted that he still opposes the bill’s card check provision — which would allow workers to form unions by petition, in addition to secret-ballot election — and its contract arbitration provisions.

But Harkin indicated last week that Specter’s hard-and-fast stance on the card check language is softening. “He’s willing to negotiate,” Harkin said. “Things are being done both at the staff level and at the member level.”

Among the alternatives being discussed, according to congressional aides and experts on labor policy, are establishing finite time windows for secret-ballot elections to take place once ordered; establishing a mail-in ballot process by which the National Labor Relations Board could not only certify but also monitor elections, thereby preventing employer interference; and the idea of “last, best offer” negotiations, where an arbitrator would choose between a union’s offer and that of an employer in setting the terms of a contract.

If senators can reach an agreement, Harkin says he will take the bill directly to the floor. That’s a turnaround from a few months ago, when he pledged to take the bill through the regular committee process.

“Everybody knows what the issues are, they already know what the amendments are probably going to be,” Harkin said. “So why do it twice?”

That is likely to upset several Republicans, but probably won’t come as much of a surprise.

“I couldn’t tell you of a labor issue that’s actually gone through regular order and through the committee in two and a half years,” said Michael Mahaffey, a spokesman for Michael B. Enzi of Wyoming, the top Republican on the Senate Health, Education, Labor and Pensions Committee.

Democratic Critics Unswayed

Opponents of the legislation say it would cost jobs during a period when the economy can least afford it, and that it would be particularly hard on small businesses struggling to survive.