WHAT HISTORY often records as a grand sweep of progress is in real time propelled by fragile moments of courage. One such moment occurred on Friday, when the Maryland House of Delegates garnered a slim majority to recognize same-sex marriage.

The 72 to 67 vote, clearing the threshold for approval by only one vote, was a dramatic and justified reversal. Last year, the march to marriage equality came to a halt in the House after conservatives and African American religious leaders expressed fears that a change in law could force religious institutions to perform marriage ceremonies that clashed with their beliefs. Theirs was an understandable concern and one that resulted in strong protections for religious organizations and their affiliates in this year’s proposal from Gov. Martin O’Malley (D). This wise accommodation rightly allayed the concerns of some and paved the way for Maryland to become the eighth jurisdiction, including the District of Columbia and, most recently before Friday, Washington state, to legalize same-sex marriage.

Firm and lasting change, we believe, is best achieved through the political process and Mr. O’Malley deserves credit for leading the campaign to allow same-sex couples in the state to share in the same rights and responsibilities as their heterosexual counterparts. Civil rights should not be a partisan issue, but only two Republicans voted for the bill: Robert A. Costa (Anne Arundel) and A. Wade Kach (Baltimore County).

Del. Tiffany T. Alston (D-Prince George’s), who sponsored a marriage equality bill last year only to reverse course after complaints from constituents, cast a “yea” vote this time to allow the measure to proceed. The bill would not have progressed without the leadership of House Speaker Michael E. Busch (D-Anne Arundel) and the support of a handful of Democrats from conservative parts of the state, including John L. Bohanan Jr. (D-St. Mary’s), who provided the 72nd vote.

The fight for marriage equality is far from over. The Senate, which passed the measure last year, is expected to once again embrace the bill, which Mr. O’Malley has pledged to sign. The law would not take effect until January 2013; in the meantime, opponents hope to gather enough signatures to put the question of same-sex marriage on the ballot in November.

The prospect of subjecting the rights of the state’s gay couples to a popularity contest is discomforting. But such are the laws in Maryland, which gives voters the power to bring a broad array of questions to referendum.

And there is reason to hope for a good outcome: A recent poll by this newspaper showed that roughly half of all the state’s residents support same-sex marriage, while 44 percent oppose the change.