WASHINGTON » Lawmakers seeking a presidential pardon for Jack Johnson, the world’s first black heavyweight boxing champion imprisoned a century ago for his romantic relationships with white women, renewed their efforts today.

Sens. Harry Reid, D-Nev., John McCain, R-Ariz., and William “Mo” Cowan, D-Mass., joined Rep. Peter King, R-N.Y., to reintroduce a resolution urging President Barack Obama to pardon Johnson because he was wronged by a racially motivated conviction.

“Jack Johnson was a legendary competitor who defined an era of American boxing and raised the bar for all American athletics,” said Reid. “Johnson’s memory was unjustly tarnished by a racially motivated criminal conviction, and it is now time to recast his legacy.”

A similar resolution passed both houses of Congress in 2009, but Obama did not act on it. The Justice Department has told the bill’s backers its general policy is not to process posthumous pardon requests. The White House declined to comment today on the measure.

Johnson, a native of Galveston, Texas, was convicted of violating the Mann Act, which made it illegal to transport women across state lines for immoral purposes.

He was hated by many white Americans, especially after retaining his title by defeating white boxer Jim Jeffries in the 1910 “Fight of the Century.” Johnson’s victory infuriated whites, sparking deadly race riots across the country.

Three years later, Johnson was convicted of violating the Mann Act.

Authorities first targeted his relationship with Lucille Cameron, who later became his wife. She refused to cooperate. They then turned to Johnson’s former mistress, a prostitute named Belle Schreiber, to testify that Johnson had paid her train fare from Pittsburgh to Chicago, for immoral purposes. An all-white jury convicted Johnson in 1913, and he skipped bail and fled the country. But in 1920, Johnson agreed to return and serve his sentence.