DEMOCRATIC presidential candidates Hillary Clinton and Barack Obama may have their hearts in the right place in opposing a trade agreement with Colombia. It’s their better judgment that is mistaken.

The two candidates are wrong about the Colombian human rights violations they cite and the jobs they hope to save for Pennsylvania workers.

The agreement, which President Bush sent this week to Congress for an up or down vote, essentially makes permanent the trade preferences that Colombia has had for 17 years. What is new is that the treaty opens the Colombian market to US exports.

The Colombian government is making the bigger sacrifice because a permanent agreement removes uncertainty for investors. Trade, combined with US support for Colombia’s military and justice system, have helped Colombia beat back a leftist insurgency, largely demobilize right-wing paramilitaries, and spark a boom that has reduced poverty, unemployment, and the economic weight of drug mafias.

Congress has been extending the temporary preferences for months at a time. Kill the trade agreement and the preferences by all logic should be killed, too. That undercuts hundreds of thousands of Colombians who work in the higher-paying new export industries.

But the unions decided that they had to show their ability to stop something, and chose this. Merits don’t matter when it’s all about demonstrating clout.