Jen DiMascio Washington

When it comes to defense spending, plans presented by presidential hopeful Mitt Romney and his new running mate Paul Ryan diverge in ways that typify an ongoing rift within the Republican Party.

But those who spend their time analyzing aerospace and defense programs see the selection of Ryan as confirmation that the Republican Party has already made a transition that does not bode well for the defense industry.

The choice of Ryan, “completes the shift away from defense hawks and toward budget hawks,” says Richard Aboulafia, an aerospace analyst with the Teal Group.

Loren Thompson, chief operating officer of the industry-funded Lexington Institute, says that the change has taken place because immediate threats to national security have receded, while defense spending has grown.

“The basic glue that holds Ryan's budget plan together is the real belief that major entitlement programs will be scaled back,” Thompson says. “When it doesn't happen, he will have to choose between raising taxes and cutting defense.”

Romney's campaign came out early reclaiming a pledge crafted by the Heritage Foundation in the 2008 election, a call to spend 4% of GDP on defense. Ryan's House Republican budget plan, called “the Path to Prosperity,” doesn't call for extreme reductions in defense spending. But it does present a four-year vision that is $1.6 trillion less than Romney's, according to Christopher Preble, vice president for defense and foreign policy studies at the libertarian CATO Institute.

The difference highlights a knotty conflict within the Republican Party, one that largely is weary with the wars begun in George W. Bush's administration and anxious to return its focus to a domestic agenda. But after 10 years of war and troops still in Afghanistan, defense hawks are continuing to push for record-high levels of Pentagon spending.