World War II, the Cold War (and its two very hot fronts, Korea and Vietnam) and the so-called War on Terror demanded that huge portions of American tax dollars were spent on the military. With the U.S. presence in Iraq ended and the withdrawal of troops from Afghanistan within sight, and with budget deficits and debt out of sight, it’s time to redefine the nation’s military.

The Budget Control Act, approved by Congress and signed by President Barack Obama in the fall, outlined some basic principles to guide this transformation. Speaking at the Pentagon on Jan 5, the president said the new plan is “smart, strategic” and sets priorities. But it will be difficult for Americans to conceive of a military that is not ready in a matter of weeks, if not days, to launch a major ground invasion.

Except that military relied on the National Guard, a largely civilian force, to sustain the Iraq occupation. And that level of military investment has come to support too much of our economy. When generals testify before Congress that they don’t want some new weapon, elected officials in whose districts the hardware is made often vote to retain the contract.

That part of the transformation from a military ready to do battle on multiple fronts to one more tailored to truly defend the nation will be difficult to achieve.

Specifically, the Administration’s plan will cut $487 billion over the next decade. And $500 billion more could be approved by Congress in the coming years.

“Some will no doubt say the spending reductions are too big; others will say they’re too small,” Mr. Obama said. “It will be easy to take issue with a particular change. But I would encourage all of us to remember what President Eisenhower once said, that ‘each proposal must be weighed in light of a broader consideration — the need to maintain balance in and among national programs.’”

The need for that balance is perhaps better understood by most Americans today than any time in the last decade. Still, in this presidential election year, some GOP candidates have waved the battered old cudgel against Mr. Obama suggesting his reluctance to launch missiles against Iran or North Korea in some imagined hypothetical scenario is evidence of being soft on terrorism or nuclear proliferation.

The lessons of Iraq will and must loom large in the coming years. The Bush administration’s plans did not anticipate the long, costly occupation and rebuilding, and failed to budget accordingly. Andrew Krepinevich, president of the Center for Strategic and Budgetary Assessments, said of the new strategy, “The attitude is no more Iraqs.” The new emphasis will be on partnering with other nations to counter threats, he said.

In this era, highly specialized training marks those at almost all levels of military service; gone are the days of relying on the grunts who take only eight weeks of basic training and a commitment to serve their country to war.

A leaner military doesn’t have to be weak. In fact, if it is more nimble and develops weapons such as drones and includes a major commitment to intelligence, it could be more effective. And, of course, spending money to help emerging nations thrive may be the best defense dollar ever invested.

It’s odd that cuts to military programs are often politically cast as something close to treason. Yet cuts to domestic programs that hurt Americans not in a hypothetical way but in very tangible terms are seen as necessary belt-tightening. It’s time to change this view.