President Barack Obama and Republican presidential nominee Mitt Romney are putting forward two very different visions for the Pentagon. But their respective policy differences pale in comparison to the economic and congressional headwinds that will confront the one who is elected next month.

The defense-policy contrasts between Romney and Obama are “important but not necessarily Earth-shattering,” says Michael O'Hanlon, a defense analyst at the center-left Brookings Institution. “You could almost imagine [Romney's proposal] as Obama 2009 versus Obama 2012 in terms of the range of debate over the proper future of our budget.”

Shadowing any promise or plan for defense spending is the possibility of an additional $500 billion cut to Pentagon spending should lawmakers fail to delay or prevent the deficit reduction penalty known as sequestration. If it happens, whoever wins in November will have to reassess his plans.

In the eyes of Obama, the military must share in efforts to reduce the deficit. But after slews of program cuts, the president is having difficulty persuading lawmakers to support the details of his fiscal 2013 budget—his first real reduction in Pentagon spending.

Romney aspires to spend $2 trillion more on defense over the next 10 years. But after former President Bill Clinton scoffed at the idea during his Democratic National Convention speech, Romney campaign advisers are describing that as a goal to be achieved over time, as the economy recovers. And O'Hanlon says that the spending gap may be far less than that—$500 billion over 10 years.

And even if sequestration is avoided, strain on the economy—and the defense budget—will remain. “Either new president is going to face very significant fiscal pressures from the debt that will put pressure on how spending is allocated,” says Nora Bensahel, a senior fellow at the Center for New American Security.

O'Hanlon and other analysts are characterizing Romney's call to spend 4% of GDP on defense as an aspiration rather than a campaign pledge. For 2013, the defense budget would return to the fiscal 2011 spending level, before Congress passed the Budget Control Act mandating a reduction in all government spending—including defense. The increase in spending would be phased in over time, explains Mackenzie Eaglen, a fellow at the American Enterprise Institute and adviser to the Romney campaign.

“This goal is predicated on a larger federal spending plan that would look very different from today's,” Eaglen writes. “Further, as tax policies are reformed, federal spending on entitlements are reformed to last longer than current budget plans would allow, and the regulatory burden is reduced on the private sector, then presumably the economy would see more growth and a 4% defense budget goal becomes more affordable.”

Eventually, additional money would allow the Pentagon to maintain 100,000 more soldiers and Marines than Obama's plan calls for. Romney would seek to build 15 ships per year, rather than the nine contained in Obama's request. He also told a Virginia television station he would order production of Lockheed Martin's F-22 Raptor to restart, though even an air power advocate suggests that might have been a misstatement—Romney might have meant buying more F-35 Joint Strike Fighters, instead.

“Romney has said he will focus on rebuilding U.S. military strength, if elected.” Eaglen says. “He believes that U.S. leadership requires a resurrection of President Ronald Reagan's vision of 'peace through strength,' where investing in hard power capabilities helps to secure national policy objectives without fighting.” Romney would value “power-projection capabilities,” make up for underfunded maintenance and modernization and fix the acquisition system, Eaglen says.

With economic growth and increased defense spending, Romney also foresees a return to larger investments in Boeing's Ground-based Midcourse Defense (GMD) System. The president canceled sites planned for installation in Poland and the Czech Republic.

“Mitt would reserve the option of reverting to [former] President [George W.] Bush's original plan of deploying proven interceptor technology in Poland if it becomes clear that Iran is making faster progress on developing long-range missiles than the Obama plan assumes or if the new technologies on which the plan relies fail to materialize in a timely fashion,” says the Romney campaign web site. “If Iran is going to deploy intercontinental missiles sooner than 2020, the United States should retain the option of defending against them.”

The economic and political pictures of 2012, however, are very different than those from 2009, which has posed problems for Obama in realizing his proposed 2013 budget.

In February, the Pentagon requested two politically unpalatable choices—a new round of base closures, and reductions to the Air National Guard's fleet.

Opposition to Obama's proposal for two years of base closures has its roots in the 2005 round, which cost money on the front end and produced vague savings on the back end. But it was also a difficult sell to lawmakers on the idea of potentially losing a major presence in their districts in an election year.

The administration later portrayed the request as setting up the idea after Obama told a Virginia television station: “You know, I don't think now is the time for [base realignment and closure]; we just went through some base closings and the strategy that we have does not call for that.”

In contrast to Romney's proposal to manufacture more F-22s, the Pentagon is still struggling with its plan to cut more than 200 Air National Guard aircraft that drew the ire of the guard, nearly all state governors and lawmakers across the country. All four congressional defense committees directed the Air Force to take a year to redraft the proposal. And Congress, which could not pass a single regular spending bill this year, united to include a rebuke of the administration's Air Guard decision in a stop-gap spending bill that will keep the government running through March 2013. That bill stipulates that no Air Force funding should be used to “retire, divest, realign, or transfer aircraft.”

The new Air Force chief of staff, Gen. Mark Welsh, has struck a conciliatory tone in recent public statements. He has pledged to improve communication, particularly with Capitol Hill and stressed the importance of unity within the service. “I have trouble seeing lines between components of services, because I believe on the air side, we have an Air Force—it has three components, but we all are working together,” Welsh said at the annual conference of the National Guard Association of the United States. “We have to, or we can't be successful.”

Internally, Obama's missile defense plan is under pressure. Since taking office, he has shifted the emphasis of the Missile Defense Agency from national missile defense to theater missile defense, implementing a phased adaptive approach (PAA) in Europe. For now, that means using SM-3 Block IA missiles on Aegis cruisers. But the latter phases of the administration's plan include a land-based presence in Poland and Romania.

A recent National Research Council report questions the final phase of the administration's long-term plan to protect the U.S. from Iranian missile attacks. “Phase IV of the European PAA may not be the best way to improve U.S. homeland defense,” says the report. “The speed of the Phase IV interceptor will need to be greater than can be achieved with a 21-in. missile to avoid being overflown by lofted ICBM trajectories from Iran if the interceptor is based in Northern Europe (Poland).” The study's co-chairs recommend fixes to the current GMD system as an alternative. That will require additional money—and, as analysts point out, that will be difficult to come by.

“There are some really hard fiscal issues they're going to have to deal with. And then defense is going to force some really hard strategic choices,” says Todd Harrison, a defense budget analyst at the Center for Strategic and Budgetary Assessments.

And this means that whoever is elected will have to deal with the next crop of lawmakers bound for Washington in January. “Either president, even within his own plan, is going to need more money to accomplish it than currently projected,” says O'Hanlon. “They're going to need to come back to Congress and ask for more money, and that's going to be complicated in a world where we could have a binding long-term budget agreement.”

With the candidates' differences on everything from investment in missile defense to organized labor and space platforms, the 2012 residential election could produce very different outcomes for the A&D industry. For more details on where Obama and Romney stand on A&D issues, check out the digital edition of AW&ST on leading tablets and smartphones, or go to AviationWeek.com/campaign2012