Most Republican lawmakers claim they are pro-trade. Their principled position is evidently no match for parochialism and politics. Last month, a conflict over imported sleeping bags between a company in Alabama and a rival in Kentucky led Senate Republicans to block the extension of the Generalized System of Preferences, or G.S.P., which has granted preferential access to some $20 billion worth of imports from developing countries.

Now Senator Jon Kyl and his colleagues in the Finance Committee are threatening to block the Trade Adjustment Assistance program, which provides income and training for American workers whose employers can’t compete with rising imports. It is due to expire on Feb. 12, and Mr. Kyl and company are refusing to extend it unless the White House promises to advance the long-pending trade deal with Colombia.

We agree that President Obama needs to press Congressional Democrats to approve the agreement without delay. But Senator Kyl’s tactics make no sense (raising questions about his motivations). His obstruction will punish American workers. It will also hurt Colombia.

That’s because Senate Democrats are refusing to support the Andean Trade Promotion and Drug Eradication Act until the trade adjustment bill passes. The preferences, also due to expire on Feb. 12, provide duty-free access to many imports from Colombia, Ecuador and Peru as part of a strategy to combat the cocaine trade by creating jobs in other export industries.