At the memorial to the USS Arizona, you can watch droplets of oil from the sunken ship drift to the surface. Some say the ship is weeping for the 1,177 service members killed at Pearl Harbor 71 years ago this week. It’s a chilling reminder of the heavy price our country paid when it was caught unprepared.

Today’s geopolitical risks are far different, of course.

Since 1945, the United States effectively has led the world, and from that position of strength we’ve redirected geopolitics. For most countries, trade is now seen as a better way to advance a nation’s interests than fighting. Most of the planet has enjoyed booming growth and soaring living standards as the American-style exchange of goods and services has helped make the free world rich.

Meanwhile, the Soviet Union tried to live outside this system and ended up collapsing. Margaret Thatcher explained that we won the Cold War “without firing a shot.” That happened because our unmatched military helped spread our ideals of free trade and opportunity around the globe, and the Russians couldn’t afford to keep up.

More recently, China decided it was better to be a competitor than an enemy. Occasional trade “wars” might erupt over particular goods, but our overarching military strength kept other countries from wanting to challenge us head to head.

Our commitment to military dominance, however, may be starting to wane.

Our Army, for example, is getting smaller. We dropped to 551,000 active-duty soldiers this year, and deeper cuts are coming next year. At least another 80,000 will be departing, even though as many as 20,000 of that number are eager to continue serving.

If the “fiscal cliff” talks that are under way in Washington fail, we could see even deeper cuts in force readiness. Under “sequestration,” the military would be required to make 12 percent to 14 percent across-the-board cuts. Army Chief of Staff Gen. Raymond T. Odierno warns that could cost another 100,000 soldiers their jobs and leave the United States with its smallest military force since 1941 – the year the Arizona was attacked.

The Navy also is being slashed.

With the USS Enterprise decommissioned, there are just 10 carriers in our fleet. That’s one fewer than Congress has demanded our fleet contain, and it’s further reduced by the fact that at any time, one of our carriers is always undergoing a “refueling and complex overhaul,” which effectively leaves the Navy with nine available carriers.

Under the waves, we’re also running short of ballistic-missile submarines. “These boats provide key deterrence and present the most survivable leg of the nuclear triad,” notes the Heritage Foundation’s Brian Slattery. “The replacement for the aging Ohio Class ballistic subs is under development, yet under President Obama’s budget – even before factoring in sequestration – the program is delayed by two years. This will cause a critical capability gap in the fleet for 14 years.”

The president famously raised this very issue during a pre-election debate. Warned that we have the fewest ships since 1917, Mr. Obama retorted: “We also have fewer horses and bayonets because the nature of our military’s changed.” Quality, he insisted, was what mattered. “The question is not a game of Battleship, where we’re counting ships. It’s what are our capabilities?”

That, of course, should be exactly the question. Defense spending should be based on a simple question: What does our military need? Yet, as Heritage’s Baker Spring wrote earlier this year, in its proposed budget, “the administration has proposed defense funding levels that are inadequate to maintaining the U.S. military capabilities described in the defense strategic review.”

That’s worth keeping in mind on Dec. 7, Pearl Harbor Remembrance Day. There’s still time to prepare, but if we want the military we need to protect the future, we must be willing to pay the bill for it.