Nearly five weeks after Mitt Romney tapped Paul Ryan (Wis.) as his vice presidential running mate, House Democrats remain publicly gleeful that the House budget chairman was added to the GOP ticket. Spurred by their belief that his selection has elevated a very winnable public debate over the future of Medicare, they are declaring Romney’s selection of Ryan an unmitigated setback for down-ballot Republicans.

Are they right? A look at recent data suggests that the outlook may not be as gloomy for the GOP as Democrats are making it sound.

Let's start with the Democratic argument.

“Paul Ryan has become a down-ballot disaster for Republicans across the country,” Democratic Congressional Campaign Committee Chairman Steve Israel (N.Y.) told reporters Thursday morning.

Israel's evidence included recent generic House ballot surveys, which have indicated a slight increase in support for Democrats during the past month. Democrats hold a slight lead in the most recent Reuters/Ipsos generic congressional ballot test after being tied with the GOP early last month. An NBC/Wall Street Journal poll showed similarly positive movement for the party.

Putting Ryan aside for a moment, there were major political developments in August that could help explain the shift toward Democrats. As Israel noted, Rep. Todd Akin’s (R-Mo.) remark that “legitimate rape” rarely causes pregnancy didn't help the GOP cause. Nor, arguably, did the attention the socially conservative planks of the GOP's platform received.

Should Ryan’s selection also be viewed as a negative factor for Republicans last month? Some key data would argue otherwise.

A mid-August Washington Post/ABC News poll showed more Americans viewed Ryan in a positive light than in a negative one. And among seniors, he was viewed even more favorably.

The latter point is especially important to keep in mind, given the Democratic efforts geared toward winning over seniors by pointing to the Ryan budget plan that revamps Medicare as a voucher system. (It’s important to note here that Ryan’s proposal would only turn Medicare into a voucher system for Americans currently 55 and under, something Democrats don’t usually mention.)

Meanwhile, a recent Washington Post-Pew Research Center poll showed that people generally associated positive words with Ryan, suggesting that Democratic efforts to brand him as an extremist and an enemy of seniors haven’t really worked.

When it comes to the messaging in individual House races, the Democratic offensive game centers more around painting Republicans as figures who “would end Medicare as we know it” than it does around linking GOP candidates to Ryan personally.

And Democrats have been playing offense in the debate over Medicare long before Romney picked Ryan as his number two. They used the issue to help them win special elections in Arizona this year and New York last year.

It’s true that the public debate over the future of Medicare has ramped up since Ryan joined the GOP ticket. Democrats see this as an advantage, even if Ryan himself is not an unpopular figure. As Israel put it, Romney "grabbed the megaphone" from them on the issue.

But Ryan’s selection has also publicly elevated the Republican counterargument on Medicare – that President Obama’s health-care law cuts Medicare by $716 billion. Republicans have been airing ads pressing this argument. (It’s important to note that the cuts referenced are to providers and insurers, not in benefit levels. And while Ryan now embraces Romney's plan to restore the cuts, he included them in his budget proposal.)

And Republicans have also learned lessons from past fumbling of the issue. As an example, last year, Democrat Kathy Hochul scored a surprise win in a New York special election that was caused, in part, by her GOP opponent’s support for the Ryan plan and lousy job articulating why she backed it. Her opponent this time around has resolved not to fall victim to the same miscues and has remained mum on Ryan’s plan.

All that said, one thing that is also clear is that dramatic changes to Medicare (like turning it into a voucher system) have not appeared to be broadly popular. And Democrats believe they can use this circumstance to their advantage. But the debate has largely become a negative one – which side is hurting Medicare more. So with Republicans also playing offense, and Ryan being afforded a bully pulpit to defend his plan and blast the Democratic one, the outlook is murky.

The jury is out on whether Ryan’s addition to the national ticket will affect the House landscape in a major way. For now at least, there is not conclusive evidence to suggest that his presence on the national ballot will mean a huge swing one way or the other.