Former New Mexico Governor Gary Johnson on Saturday called an anti-gay marriage pledge “offensive and unrepublican.”

Johnson, who declared in April his candidacy for the 2012 GOP presidential nomination, is among the field's most gay-friendly candidates.

The 58-year-old Johnson believes government should not intervene unnecessarily in the private lives of individual citizens and supports civil unions for gay and lesbian couples.

In a statement posted at his campaign website, Johnson blasted Christian conservative group The Family Leader's pledge, titled The Marriage Vow: A Declaration of Dependence Upon Marriage and Family, saying it gave Republicans a bad name.

The two-page document – introduced Thursday and sent to GOP candidates and President Barack Obama – asks candidates to “vigorously” oppose marriage equality, be faithful to their own spouse, vow to protect women and children from pornography and reject Sharia law because it is a “form of totalitarian control.” The group, influential among social conservatives, has said it will not endorse any candidate that does not sign the pledge.

This 'pledge' is nothing short of a promise to discriminate against everyone who makes a personal choice that doesn't fit into a particular definition of 'virtue,'” Johnson wrote.

“While the Family Leader pledge covers just about every other so-called virtue they can think of, the one that is conspicuously missing is tolerance. In one concise document, they manage to condemn gays, single parents, single individuals, divorcees, Muslims, gays in the military, unmarried couples, women who choose to have abortions, and everyone else who doesn't fit in a Norman Rockwell painting.”

“The Republican Party cannot afford to have a Presidential candidate who condones intolerance, bigotry and the denial of liberty to the citizens of this country,” he added.

Minnesota Representative Michele Bachmann and former Pennsylvania Senator Rick Santorum were the first candidates to sign the pledge.