Hare told two dozen people at a Rock Island union hall that U.S. prestige would suffer if it rewards a country where union members have been murdered at a rate of one a week and only a fraction of the perpetrators have been brought to justice.

“They need to start arresting people instead of releasing people,” he said.

Hare joined other Democrats on Thursday in voting on a rule that delays consideration of the trade deal, which the Bush administration submitted this week. The delay could kill the deal for the year.

Backers of the Colombia pact say it would boost exports by $1 billion, with the administration estimating it would increase trade in Iowa by $33 million and nearly $310 million in Illinois.

Notably, Caterpillar’s plant in Decatur, which is in Hare’s district, would benefit from the deal because it would lower tariffs 15 percent on off-highway trucks and motor graders. Caterpillar does a lot of business in Colombia.

“It would have made our products a lot more competitive,” said Bill Lane, the company’s director of governmental affairs in Washington, D.C.

Caterpillar has seen sales and exports growing recently and has added workers as a result.

Hare said he wants to help Caterpillar, but he argued Friday the trade deal falls flat on more than just humanitarian grounds.

He said that such deals hurt American workers, just as he says NAFTA has. And he said he would be more amenable to trade deals if the Bush administration would support a House-approved bill to provide benefits to displaced workers and enforce provisions of previous trade agreements.

“Somebody’s got to stand up for the American worker,” he said.

A spokesman for Rep. Bruce Braley, D-Iowa, said he’s uncommitted on the Colombia deal but is leaning against it. He also voted for the rule change that delayed consideration.

Labor unions and human rights groups are opposing the Colombia deal, while business groups are by and large in favor of it.

“It’s going to level the playing field for U.S. exporters,” said Laura Narvais, a spokeswoman for the National Association of Manufacturers.

The administration and the Colombian government say it has improved its human rights record.

Colombia says it’s doubled funding the past four years for measures aimed at reducing the violence and accelerated prosecutions. Assassinations also have dropped by 40 percent between 2002 and 2008, the government said.

Human rights groups say the trade deal should be delayed until Colombia demonstrates meaningful change.

Hare, one of the most vocal critics in the House of U.S. trade policy, has taken on a more visible role in fighting trade deals.

He voted last year against a trade deal with Peru, which passed the House, and is a member of the House Trade Working Group. The group is critical of U.S. trade policy.