This was an historic week in U.S. political history. No Democrat can now seriously run for president, and survive a primary, without supporting gay marriage. Why? Ohio Sen. Rob PortmanRob PortmanOvernight Finance: Senators spar over Wall Street at SEC pick's hearing | New CBO score for ObamaCare bill | Agency signs off on Trump DC hotel lease GOP senators offer bill to require spending cuts with debt-limit hikes Vulnerable Senate Dem: Border tax concerning for agriculture MORE, a conservative Republican, came out in favor of same-sex marriage, followed immediately by a video announcement from Hillary ClintonHillary Rodham ClintonComet Ping Pong shooter pleads guilty Time for 'J. Edgar' Comey to take his leave Corruption trial could roil NJ Senate race MORE (why wait for an interview?) declaring her support for the same. Then an ABC News/Washington Post poll released Monday showed that an all-time high of 58 percent of the country now supports same-sex marriage, up an astonishing 26 percent in just nine years.

The issue is now a litmus test in Democratic presidential politics, the exact opposite from 2008, the last open election, when no Democrat seeking the Oval Office would dare sanction marriage for anyone but one man and one woman for fear of tainting themselves for the general election. On this issue, most of the general election will now be behind them. Not so for Republicans, who would struggle in a GOP presidential primary among evangelical Christians who have enormous influence in the primary process. Their support may be an insurmountable hurdle. David Brody of the Christian Broadcasting Network questioned this week whether the GOP would lose evangelicals by remaining silent on the issue of gay marriage.

Clinton's announcement was clearly on its way, with her husband less than subtly laying the groundwork two weeks ago with his declaration of regret over signing the Defense of Marriage Act. After all, two gay-marriage cases reach the U.S. Supreme Court next week, and Clinton thought it the perfect time to announce her support in advance. But there's a pretty good chance she rushed out her video as soon as Portman's surprise announcement just days before. No matter what, it means Clinton doesn't want the 2016 presidential speculation to leave her out.

Just sayin'.

SEN. JOHN MCCAIN IS NOW URGING A GRAND BARGAIN WITH NEW REVENUE? IS THERE HOPE? AskAB returns Tuesday, April 2 after a cold spring break. Please join my weekly video Q&A by sending your questions and comments to Thank you.