What makes Olson's involvement in the same-sex marriage litigation so interesting - and among right-of-center lawyers, controversial - is that his position is relying on the kinds of constitutional arguments that Olson is personally so closely identified with rejecting. The Times story touches on this, but I would add a bit more detail. Those who have watched Olson's annual Supreme Court Roundups for the Federalist Society know how harsh Olson tends to be about judges who Olson thinks are constitutionalizing their policy views, especially when that means constitutionalizing social policies popular among elites. Olson hasn't just been critical of those who take a broad view of constitutional meaning in this setting: he has been dismissive and sometimes even brutal.
The surprising aspect of the new case is that it has Olson making same kinds of constitutional arguments that he has specialized in ridiculing for so long. It's the juxtaposition that is surprising. Of course, different people will disagree on which Ted Olson is right. Some will say he was wrong before and right now; others will he was right then and wrong now. But however you look at it, it seems hard to reconcile the two.
Olson's lawsuit is not the only one filed this year that seeks to advance marriage equality. Early this year, the Gay and Lesbian Advocates and Defenders (GLAD) lodged a lawsuit against the Defense of Marriage Act (DOMA), saying the federal law deprives legally married same-sex couples in Massachusetts and Connecticut of economic benefits that go to heterosexual couples. More on GLAD's lawsuit is here.