Wisconsin Rep. Paul Ryan accepted the Republican Party’s nomination for vice president Wednesday with a speech that showed he was not afraid to take on Obama.

While pushing his outline for smaller government, he took several swipes at the U.S. president.

“Ladies and gentlemen, these past four years we have suffered no shortage of words in the White House,” he said. “What’s missing is leadership in the White House.”

Ryan even took on the left over health care, traditionally a weak suit for the Republicans, and the subject of Obama’s proudest legislative achievement. He said Obama’s federal health care law threatened Medicare’s survival.

“A Romney-Ryan administration will protect and strengthen Medicare, for my mom’s generation, for my generation, and for my kids and yours,” Ryan said.

“Our opponents can consider themselves on notice. In this election, on this issue, the usual posturing on the left isn’t going to work. Mitt Romney and I know the difference between protecting a program and raiding it.”

The attack prompted rapturous applause ― perhaps because he didn’t mention that his plans would also cut funding for Medicare.

By all accounts his speech was well received, earning several ovations. But Ryan’s task goes beyond attacking Obama and selling policies. His biggest task may be convincing the American public that Romney should be their next president.

One of the biggest weaknesses of John McCain’s bid for the White House in 2008 was that, while Obama oozed charisma, McCain struggled to look like a leader.

Romney has been criticized for looking stilted in public appearances and uncomfortable when venturing off-script. For all the dissatisfaction many Americans have with Obama, he still retains a presidential air.

Perhaps his running mate can instill some confidence and polish into the campaign. If not, Ryan may find Romney his most difficult sell.

By Paul Kerry (paulkerry@heraldcorp.com)