A cloture vote on fast-track trade legislation—known formally as Trade Promotion Authority (TPA)—is expected Tuesday. A vote on TPA itself could come as early as Wednesday. Whether it passes or fails depends on whether the pro-TPA alliance between most Senate Republicans and the 14 Democrats who voted for TPA a month ago can stick together. At the moment, odds are in favor of passage.

That original vote of 62-37 was just two more than needed. For the grassroots coalition that has been lined up against fast-tracking for more than a year, shifting enough votes to keep TPA from passing again is going to be a very difficult struggle. Changing minds may well depend on whether at least three Democrats find they cannot trust Republicans to carry through on their promise to pass another trade bill reauthorizing the program of workers' aid legislation called Trade Adjustment Assistance (TAA).

TAA provides job training, some financial assistance and healthcare coverage for workers displaced by trade agreements. Some left-of-center critics say TAA, which has accompanied trade agreements since 1974, does far too little to aid workers displaced by trade agreements and that it's just not good enough to pass fast-tracking, which may lead to trade pacts that displace those workers in the first place. Others say it's better than nothing. In terms of getting enough Democratic votes to pass TPA in May, however, it was crucial even though Republicans, who view TAA as wasteful welfare, grumbled about being pushed by the Senate leadership to support it.

It was agreed to tie TPA and TAA together. If the former passed but the latter didn't, the trade legislation could not be sent to the president. That fact is what led the anti-fast-track coalition to encourage House Democrats to reject TAA, thus keeping TPA in limbo since the pairing of the two meant the president couldn't sign one without the other. That successful maneuver kindled a House Republican counter-move last week, passing TPA without tying its success to passage of TAA.

Now, it's a matter of the pro-TPA forces persuading those 14 Democrats that Republicans (who would kill TAA if they could) will vote for it after TPA is approved, if it is. The proposal would add TAA to another bill—the African Growth and Opportunity Act (AG0A)—after the TPA vote. If this clears the Senate, then the AGOA/TAA bill will be sent to the House for a final vote.

That could be a hang-up if enough House Republicans choose to oppose the bill. But it seems unlikely enough they will make that choice. And this time around the reauthorization is likely to see most Democrats vote for it since TPA would be a done deal.

What happens in the Senate thus matters most. And the vote of those 14 Senate Democrats will depend on whether they believe Republicans will carry through on TAA.

What is the level of that trust? Follow me below the fold.

Join us in urging senators to vote against TPA, fast-track trade legislation.