By DEB RIECHMANN
Associated Press

(WASHINGTON, AP) — Treasury Secretary Jack Lew warned Wednesday against the overuse of financial sanctions against other nations and said the U.S. must be prepared to ease the penalties over time if they succeed in changing behavior.

Lew said the United States must guard against the “impulse to reach for sanctions too lightly,” especially in situations where they will have a negligible effect. Sanctions can strain diplomatic relationships, introduce instability into the global economy, impose costs on companies in the United States and abroad and carry the risk of retaliation, he said.

“We must be conscious of the risk that overuse of sanctions could undermine our leadership position in the global economy, and the effectiveness of our sanctions themselves,” Lew said in a speech at the Carnegie Endowment for International Peace.

“If foreign jurisdictions and companies feel that we will deploy sanctions without sufficient justification or for inappropriate reasons … we should not be surprised if they look for ways to avoid doing business in the United States or in U.S. dollars.”

Lew gave his speech about lessons learned on decades of sanctions at the same time that some Republicans in Congress want to keep hard-hitting sanctions in place against Iran. They were against last year’s nuclear agreement in which the U.S. and its allies agreed to ease sanctions against Tehran in exchange for its promise to curtail programs that would allow it to develop nuclear weapons.

“Since the goal of sanctions is to pressure bad actors to change their policy, we must be prepared to provide relief from sanctions when they succeed,” he said. “If we fail to follow through, we undermine our own credibility and damage our ability to use sanctions to drive policy change. … Since Iran has kept its end of the deal, it is our responsibility to uphold ours in both letter and spirit.”

Republicans in Congress are still angered by the Iran nuclear deal that they contend was a better deal for Tehran than it was for the U.S. and its allies. Last week, House Speaker Paul Ryan hammered the Obama administration for the nuclear deal with Iran, telling America’s leading pro-Israel group that the agreement legitimized Iran’s nuclear program instead of dismantling it.

GOP lawmakers also have criticized Obama for failing to properly punish Iran for repeatedly defying a U.N. ballistic missile test ban. A group of Republican senators last week introduced legislation to impose stricter sanctions on every sector of Iran’s economy that supports the country’s ballistic missile program. The administration imposed sanctions against Tehran for missile firings, but Republicans say they the measures were too weak.

Republican also have expressed concern that the Obama administration is leaving the door open to new sanctions relief for Iran, including possibly long-forbidden access to the U.S. financial market. Rep. Ed Royce, the House Foreign Affairs Committee chairman, expressed alarm in a letter to the president that the U.S. could grant Iranian businesses the ability to conduct transactions in dollars within the United States or through offshore banks. House Majority Leader Kevin McCarthy, R-Calif., said he is “deeply troubled” by the possibility.