President Bush's proposed defense budget for next year — an inflation-adjusted $515 billion — stands as the most dollars ponied up for the Pentagon since World War II. At first glance, that seems out of whack. How can it cost almost as much to chase after Osama bin Laden as it did to beat both Adolf Hitler and Hideki Tojo?

But what's out of whack isn't the spending, it's the comparison. We're talking apples-to-oranges.

Comparing the cost of today's military to what America spent to equip and deploy GIs against the Nazis is like comparing today's home entertainment center — plasma-screen, surround-sound HDTV with PlayStation 3 and Wii — to Harry Truman's Philco radio. Sure, today's system costs a lot more. But look what you're getting.

The high-tech gadgets that amplify the power of our military aren't just bells and whistles to brag about. Both "smart" weapons and battlefield medical advances, for example, cost more in real dollars. But they dramatically reduce the cost in lives — civilian as well as military.

Our tactics and technology are now so calibrated and surgical that it's no longer necessary to devastate entire cities, Dresden-style, to secure a decisive victory for freedom. Fighting war more humanely isn't cheap.

Even more important, you're getting an all-volunteer force, better educated and better trained the any of the conscript forces used in prior conflicts. Highly skilled volunteers cost much more, but they're worth it.

And economies improve — just like technology and skills. America's economy when almost everyone seemed to "like Ike" can't begin to compare with that of today, when so many like to bash Bush.

It cost almost 50 percent of the nation's gross domestic product (GDP) to pay for World War II. Fighting the Korean War consumed about 14 percent of GDP, Vietnam about 9 percent.

Even with supplemental spending to fight radical Islamist terrorists in Iraq and Afghanistan, the president's defense budget is about 4 percent of GDP. America is engaged in a Long War. We should be prepared to pay for it.

The good news is that, compared to the last long war — the "Cold" one — the relative burden is far more bearable. To hold off the Soviets, the United States averaged defense spending of about 7½ percent of GDP for 40 years. Still, our economy grew.

In fact, the economy did some of its fastest growing after President Reagan defense build-up got under way. Today's $13 trillion economy is more than 4 times bigger than the economy of 1983, Reagan's third year in office.

Look at it this way: We dedicated more than three-quarters of the federal budget to winning World War II. Today we spend only one-fifth of the budget on defense, volunteer forces and awesome weaponry included. Spending on Social Security, Medicare and Medicaid dwarfs that.

Today's military is a bargain. America is a global power with global responsibility. True, we spend far more on defense than any other country. But America bears far more burdens as well.

Over the long term, defense spending as a percentage of GDP is the appropriate way to measure our national commitment to keeping America safe, free and prosperous. That's the number policymakers should keep in mind as they look at the president's budget.