President Bush has sailed the Colombia free trade agreement into uncharted waters. House Speaker Nancy Pelosi (D-Calif.) now faces the task of navigating them.

Bush has put her in a tricky position by trying to force Democrats into a vote on the deal, which is strongly opposed by labor unions.

Normally, presidents only send trade deals to lawmakers when they are reasonably sure of a positive outcome — which is why Congress has never voted one down.

In this case, however, an unpopular Republican president in his final year of office is sending a controversial deal to a Congress controlled by a rival party that believes it is poised to take the White House and thus monopoly control of Washington. Because the Colombia deal is subject to a fast-track law, Congress faces a 90-legislative-day clock to take action.  

Bush’s move is a direct challenge; Pelosi has three options, all of them risky.

She could try to negotiate with Bush to allow Democratic leaders to support the Colombia deal, but this would be difficult given opposition from labor unions, who see a golden opportunity to defeat a trade deal in an election year. Opposition from both Democratic presidential candidates makes this even tougher.

Pelosi could instead kill the bill on the floor, which would be celebrated by unions and their congressional allies. But Pelosi probably does not want to be the first Speaker to oversee the defeat of a trade deal, a diplomatic and foreign policy reverse that would be criticized around the world.

In addition, Colombia is a loyal U.S. ally in a part of the world where Venezuelan President Hugo Chavez’s anti-U.S. rhetoric resonates. Chavez would declare victory if the trade deal is defeated. Pelosi cannot want to be seen helping him.

That leaves option No. 3: Bottle up the trade deal. Fast-track is designed to ensure trade agreements cannot be controlled in committee or amended to death on the Senate floor. But it does not govern the House Rules Committee. Trade lobbyists believe Pelosi could construct a rule that would recommit legislation implementing the deal back to committee.

This would be her safest route, for it would avoid a row with labor unions while avoiding the baleful glare of international opinion and of history.

Yet this third option could also have unwanted consequences. It would raise serious questions about the applicability of future fast-track laws, which are needed to give the executive branch the power to negotiate on trade. It could handcuff a future Democratic president, and it is uncertain what its impact would be on the Colombia deal.

Bush’s decision to send the deal to Congress was an obvious one for a lame-duck administration focused on its legacy. How it affects future executive-congressional relations on trade is unknown.

Pelosi faces a real challenge to her leadership.