Rep. Paul Ryan (R-Wis.) speaks Wednesday at the Center for a New American Security’s annual National Security Conference in Washington Credit: Associated Press

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Washington — Accusing President Barack Obama of weakness on the world stage, Wisconsin Republican Paul Ryan argued Wednesday for a military buildup, for a more vigorous foreign policy vision, and against a U.S. troop withdrawal from Afghanistan "before we finish the job."

"Our friends think we're adrift, our rivals think we're sinking, our credibility is at risk, and so with it, our security," said Ryan, the House budget chairman who waded into a running foreign policy debate between the parties and within the GOP over U.S. strategy, leadership and intervention abroad.

"We can't withdraw from the world. We have to stay engaged," he said.

Ryan was one of the featured speakers at a security conference in Washington, which occurred the day after Ryan's friend and close colleague, House Majority Leader Eric Cantor, suffered a shocking defeat in the Virginia GOP primary to a more conservative challenger.

Speaking briefly to the Milwaukee Journal Sentinel after the speech, Ryan said he was "totally shocked by Cantor's defeat," but squelched any speculation he might be interested in stepping into the House GOP leadership void after Cantor's departure from Congress.

"My position has not changed. I'm not interested in (House) leadership," Ryan said in the interview. "That's just not been my interest."

At the conference hosted by the Center for a New American Security, Ryan said his call for more military capacity was not a call for more military interventions.

"We have to develop our military. But we shouldn't be quick to use it," said Ryan, the 2012 Republican vice presidential nominee and potential candidate for president in 2016 who described himself to the foreign policy audience as a "budget guy" who doesn't "get to talk about national security as much as I'd like."

"American leadership doesn't demand a more militarized foreign policy, but a more creative one," he said. "We prepare for war so we can keep the peace."

Ryan said of Obama's defense budgets, "Every year he cuts so deeply — and so unevenly — that he's hurting both our current and our future capabilities."

The Janesville congressman conceded that money for the military has not always been spent well or efficiently, saying the process of buying new weapons systems requires continued reform.

Ryan had sharp words for China in the speech:

"With its new power, China isn't trying to bend the rules — in many ways it's trying to rewrite them altogether. It's stealing our intellectual property. It's attacking our companies. It's promoting crony capitalism. In a narrow-minded pursuit of its narrow self-interest, China isn't trying to uphold market principles but in many respects it's trying to upend them."

He accused Obama of failing to back up words with actions and failing to speak with enough moral vision in foreign affairs, saying, "When Russia invaded Ukraine, the president spoke with all the moral outrage of an instruction manual."

Said Ryan: "The world isn't perfect, and we shouldn't try to make it so. To say we're the leader is not to say we're always the enforcer. Instead, we're the chief advocate — for our interests and our principles — because a lot of people in the world share our principles."

Ryan called for not only more military spending, but said that reforming entitlements and paying down the national debt were steps the U.S. needed to take to preserve its own leadership and credibility in the world.

"The greatest threat to American leadership is our national debt," he said.

Ryan is the architect of House budgets that call for reducing spending on entitlements such as Medicare, changing the way they are structured, and spending a much smaller portion of the federal budget on domestic programs in future years.