President Obama said he has a "grudging admiration" for the way Senate Minority Leader Mitch McConnell's (R-Ky.) managed to hold Senate Republicans together to oppose Democrats' agenda over the last year and a half.

The president said he was disappointed in the way the Senate often has moved since January of 2009 to stall or kill top pieces of his agenda, though Obama suggested that he thought the leading Senate Republican was a worthy foe.

"What I was surprised somewhat by, and disappointed by, although I've got to give some grudging admiration for just how effective it's been, was the degree to which Mitch McConnell was able to keep his caucus together on a lot of issues," Obama said in an interview in this month's Rolling Stone.

Obama has often complained about "obstructionism" of his initiatives in the Senate, where McConnell leads a conference of just 41 votes. Before Sen. Scott Brown (R-Mass.) was elected in January, the GOP only had 40 seats in the upper chamber — not enough to sustain a filibuster without Democratic help.

Nonetheless, McConnell's been an adept opponent of the Democratic agenda, having used Senate rules and procedures to slow down and halt progress on bills the GOP dislikes. That's required an extraordinary amount of party unity on top issues. The Kentucky senator lost no votes on healthcare reform, for instance, and only a few Republicans broke with the conference on Wall Street reform and the stimulus.

Obama said his strategy had been to wear down Republicans in the Senate with a blitz of bad attention. (The president had railed, for instance, all of August against Senate Republicans for having blocked the small-business bill he eventually signed this week.)

"Eventually, we were able to wear them down, so that we were able to finally get really important laws passed, some of which haven't gotten a lot of attention," Obama explained. "We'd be able to pick off two or three Republicans who wanted to do the right thing."