President James Madison made a major strategic foreign policy mistake that undermined his effort to persuade Britain to repeal its commercial restriction against American trade when he a. accepted Napoleon's promise to repeal its trade restrictions. b. failed to suppress the war hawks in his own party. c. permitted Napoleon to offer financial aid to the United States.

Explanation:

President James Madison in an attempt to show support and inclination towards France made a strategic foreign policy mistake which had heavy repercussions.

During that point of time, France and Britain were rivals and the decision made by President Madison to accept Napoleon's promise to repeal its trade restrictions aggravated Britain.

With the passage of the Macon’s Bill No. 2 by Congress, it further heated the relation with Britain. The U.S had to impose an embargo to Britain as she did not follow the demand of the bill.

The embargo on Britain in return led to a number of challenges and only  proved that U.S was not in position to challenge the British government during that time.