While Democrats are claiming that gun control is hurting Republicans, how come Obama is so far underwater on the issue?

I have been very skeptical of the claims that Republicans have been hurt by their opposition to the Senate gun control bill.  Yet, it is curious that Obama's low approval rating on the gun issue isn't getting similar attention.  From Politico:

On gun policy, some 52 percent disapprove of his approach, while 41 percent approve. That could be due in part to the loss in the Senate of the gun control proposal he pushed for expanded background checks for gun buyers. . . .

BTW, it is interesting to see that Obama's handling of immigration is also underwater.

Compare the media coverage with Senator Kelly Ayotte and her vote on guns with the media coverage with Obama's low standing on the gun issue.  This also from Politico:

Pro-gun control activists, who attended the meeting, were incensed. Security brushed aside two women who approached Ayotte and demanded to speak with the first-term Republican about her vote against expanded background checks for commercial gun sales, underscoring the lingering controversy that continues to hover over the New Hampshire senator. . . . 

The emotional fight threatens to transform Ayotte — a young conservative Republican woman whose star is on the rise — into a polarizing figure back home on a contentious issue. Instead of taking up the banner of gun rights, Ayotte is seeking a lower profile on the subject in a state where she’s become the last Republican in the all-female congressional delegation. 

“It hurts her,” said Kathy Sullivan, a longtime Democratic operative and former head of the state party here. “Elections are won in New Hampshire with the vote of independents, particularly independent women. Independent women will not favor a candidate who does not believe in background checks. Will it be the only issue? No, but it will be an issue.” . . .