And simultaneously twists himself into a pretzel in the process…..   He proclaims that “Defining Marriage”, and by consequence what genders/species can be considered “married” is, to him, a state issue.    That is on one hand.

But, on the other hand, President Obama holds simultaneous opinion that “Abortion”, or in a larger context “pregnancy or the elimination thereof”, is a federal issue.
This is the same non-reconcilable progressive ideological leftist hypocrisy that continually happens when the institutional left attempts advocacy or even disparagement toward an opposing advocacy.  (more on that another day)
For now his Tenth Amendment supportive position is politically leveraged.  Highly politically leveraged, because New York, unlike all other legal constructs of previous gay marriage, has required reciprocity within their legislation.    Meaning, they did not attach a paragraph accepting that other states are not bound to recognize the contract.  New York has bound all other 49 states to recognizing their definition marriage.
This reciprocity conflict will lead the New York marriage law eventually into the Supreme Court, there is no other way around it.    Either SCOTUS will have to define “legal marriage”, or they will affirm the 10th amendment.
Unlike Obama, the Supreme Court cannot have it both ways.   The consequence of SCOTUS defined marriage would federalize legislation and override the states.    If SCOTUS affirms states rights to define, the consequence would strike down the New York law, and force NY to restructure their law.   Duplicating the law in all other gay marriage states who cannot, and do not, bind the republic with reciprocity.  
(The Hill) — President Obama on Wednesday endorsed gay marriage, becoming the first U.S. president to voice support for same-sex couples to legally marry.
The announcement is a landmark for the gay rights movement, which has battled for decades to win legal recognition for same-sex marriages.
Yes the sudden pivot by Obama in an election year on the explosive issue exposes his campaign’s risks, which could alienate some socially conservative, independent voters who do not support the issue.
Obama’s admission his gay marriage stance comes days after Vice President Joe Biden said he was “absolutely comfortable” with gay marriage. Education secretary Arne Duncan also admitted earlier this week that he also supports gay marriage.  (more)
Washington Post – “I’ve just concluded that for me personally it is important for me to go ahead and affirm that I think same-sex couples should be able to get married,” Obama told Robin Roberts, in an interview to appear on ABC’s “Good Morning America” Thursday.
Obama went on to explain that he had “hesitated” on marriage because he thought same-sex unions would be “sufficient” in order to guarantee rights for couples such as hospital visitations. And he said he wanted to be “sensitive” to the fact that for many Americans, the word “marriage” evokes “very powerful positions, religious beliefs and so forth.”
ABC will air the interview on its evening news Wednesday night and on “Good Morning American” Thursday. In a brief special this afternoon, Roberts said that Obama invoked his daughters, and conversations over dinner in which they have said that some of their friends have gay parents.
Asked if he was forced into the announcement because of Biden’s remarks over the weekend, Roberts said that Obama laughed and explained that he and his aides had been engaged in the discussion for some time.
The president has been under intense pressure for his self-described “evolving” position on the issue since Sunday, when NBC aired an interview in which Vice President Biden said he was “absolutely comfortable” with gay marriage.  (more)