With rumors swirling that the Employee Free Choice Act (EFCA) may be introduced as early as tomorrow, both union and business interests have marshaled their forces in Washington. Both sides plan to descend on Congress this week in an effort to sway the remaining Senate holdouts. It seems increasingly likely that EFCA will be introduced in the Senate first, as support in the Senate is more tenuous than that in the House. Unions will have their work cut out for them, however, as even EFCA supporters have begun to acknowledge that gaining enough votes to invoke cloture – and thus avoid the inevitable filibuster – has become something of an uphill battle.

On ABC’s This Week, Sen. Claire McCaskill (D-Mo.) admitted: “I’m not sure that we have the votes” for cloture. Among those with wavering support are Sens. Blanche Lincoln (D-Ark.) and Mary Landrieu (D-La.), who will no doubt be prime targets for this week’s lobbying campaign. Democratic senators in right-to-work states also face pressure from their business constituents to oppose the bill. EFCA fell nine votes short in the Senate when it was first introduced in 2007, so every vote is critical. Although EFCA’s passage in the House is virtually guaranteed, some Democratic representatives have already voiced their opposition. On Friday, Rep. Dan Boren (D-Okla.) became the first House Democrat to openly declare his position against EFCA. More could follow. Until then, it will certainly be an interesting week. Among the possibilities to watch for is the potential for negotiations that could transform EFCA into something that might convince middle of the road Senators to support it.