More than five days after Rep. Paul Ryan was announced as Gov. Mitt Romney's running mate, it is clear that Democrats--and their mainstream media friends--are losing the race to define him. First, they tried to describe him as too conservative: his budget plans were too bold, his pro-life positions too strong. That failed--even in Florida. So now it's on to Plan B: attempting to chip away at conservative enthusiasm for the Romney/Ryan ticket by digging for alleged past deviations from partisan orthodoxy--as they have done with Romney himself.

A hint of this new strategy appeared in The Hill today in a piece by Mike Lillis, which is rather fair to Ryan but still manages to reveal some of what Democrats may plan to seize upon:

Rep. Paul Ryan's (R-Wis.) shifting position on immigration over the years has left advocates on both sides of the thorny issue uneasy about his possible ascension to the White House.

Mitt Romney's newly named running mate was groomed by pro-immigration Republicans and has a long history of backing bills granting some illegal immigrants legal status — proposals blasted by conservative hard-liners as granting "amnesty" to "law-breakers." But Ryan also has a record of supporting tougher enforcement measures, and recently vowed to oppose any "amnesty" proposals — a rightward shift that has immigrant-rights groups up in arms.

Expect such stories to be amplified by the Obama/Biden rapid response team in the coming days. It is the same strategy that the Chicago Democratic clique tried in the 2010 race for U.S. Senate between then-Rep. Mark Kirk and Illinois treasurer Alexi Giannoulias. Knowing that Kirk had damaged his conservative support by voting for President Barack Obama's cap-and-trade bill in 2009, Democrats reminded voters--Republicans in particular--at every opportunity that Kirk had let them down and was therefore not to be trusted. The strategy did not work--and may even have backfired, as a significant number of moderate Democrats crossed over to vote for and donate to Kirk, often on the basis of his strong record on foreign policy and national security. 

It is no secret to conservatives that Paul Ryan has not always voted the party line--or the ideological line. He has faced criticism for supporting the Troubled Asset Relief Program in 2008, for example. But that is old new to conservatives. What is new is that he has led the debate for fiscal reform in Washington, making a conservative argument for limited government and rapid economic growth that has won praise from the Tea Party and respect from colleagues across the aisle. There is growing evidence in the polls that Ryan is energizing the conservative base--and winning approval from former Obama voters eager to embrace new leaders and ideas.

That means Plan B isn't likely to work, either--and so the Obama campaign will eventually shift again to attacking Romney directly, especially with Vice President Joe Biden making Ryan's job easy. And when Romney answers, he'll be bolstered by Ryan, who thus far has managed to brush aside everything Democrats have thrown at him.