With his usual thoroughness John Lott said:

Possibly one of the more remarkable changes has been his position on guns.
But despite Obama’s recent concession on “The NewsHour with Jim Lehrer” that there has been a “shift in emphasis” on various issues, on guns he held firm: “You mentioned the gun position. I’ve been talking about the Second Amendment being an individual right for the last year and a half. So there wasn’t a shift there.”
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No matter Obama’s current position, no major party presidential nominee has probably ever had as strong and consistent an anti-gun record. Here is a politician who supported a ban on handguns in 1996, backed a ban on the sale of all semiautomatic guns in 1998 (a ban that would encompass the vast majority of guns sold in the U.S.), advocated in 2004 banning gun sales within five miles of a school or park (essentially a ban on virtually all gun stores), as well as served on the board of the Joyce Foundation, probably the largest private funder of anti-gun and pro-ban research in the country.

In a post Heller world Obama is the equivalent of someone who owned slaves two years ago now claiming he always believed slavery was wrong. If he really believed what he claims then he should have acted on his beliefs instead of what was most advantageous to him at the moment.