Two weeks after signing Maryland’s same-sex marriage bill into law, Gov. Martin O’Malley (D) is scheduled to address a national conference of Catholics who support gay rights.

Gov. Martin O’Malley (D) at theMarch 1 signing of Maryland’s same-sex marriage bill. (AP Photo/Patrick Semansky)

“As Catholics, we are proud of Governor O’Malley’s ardent support of marriage equality,” said Francis DeBernardo, the group’s executive director. “His support is in the best tradition of Catholicism’s legacy of social justice for all.”

O’Malley’s appearance comes as opponents of the new law conduct a petition drive aimed at putting the isuse to voters in November. O’Malley has conceded it is likely that the petition drive will succeed.

In July, Edwin F. O’Brien, then the archbishop of Baltimore, wrote a letter to O’Malley saying his sponsorship of a same-sex marriage bill would “deeply conflict” with O’Malley’s Catholic faith and that he should resist political pressure to do so.

O’Malley wrote in response:”When shortcomings in our laws bring about a result that is unjust, I have a public obligation to try to change that injustice.”