Was Mitt Romney slipping before naming Rep. Paul Ryan (R-Wis.) as his running mate, and is Ryan helping him to rebound?

As I’ve warned multiple times, polling months before an election is a dicey business. And polls that over-sample voters from one or the other party are relatively meaningless. So encouraging battleground state polls that show Romney’s numbers rising shouldn’t freak out the Democrats nor give Republicans all that much comfort. And for those on the right who didn’t buy certain national polls showing President Obama had stretched to a big lead, the latest batch simply suggests the race is where it has been for much of the campaign — that is, within the margin of error.

But there is no mistaking the mood in the Romney camp: It is somewhere between relief and elation that the campaign is back on its feet and once again on offense. Campaign advisors with whom I spoke over the last couple of days resist cockiness, but the sense is that the campaign is doing what it must and putting itself in a good position for the convention and the debates.

Romney advisers think the campaign’s welfare ad is contributing to the uptick and are convinced Obama’s invitation to states to seek waivers of the work requirement is toxic for Obama with working- and middle-class voters in swing states.

Romney advisers see the Ryan announcement and the rallies that followed as exceptionally successful, in part because Ryan’s positive influence on Romney’s mood and message wasn’t fully anticipated in Boston.

Moreover, Romney isn’t going to be outspent from here on out. He can match the Obama team (ad for ad with some left over for more) in battleground states.

So if you add Ryan to the ticket, find an effective issue with which to bash your opponent, get off defense and rattle the other side on everything from its tone to its pet issue (Medicare), it’s not inconceivable that you might edge up in the polls.

A Romney adviser told me that the day Ryan was officially announced was the “first day of the convention bump.” That’s the game plan, at any rate: Build momentum going into Tampa, deliver rousing speeches that help puncture the negative image Obama is trying to create, roll out the ad tsunami with the huge amounts raised this summer, and sprint to the end, they hope, with solid debate performances. All of that requires execution, nimbleness and attention to detail, which at times have not been evident in the Romney operation. The recent display of political dexterity is encouraging to Republicans, even to some of the worrywarts who thought Ryan would be a drag on the ticket.