How many ground troops does the United States need?

Answering that question depends on your vision of the future -- specifically, the military challenges the United States will face over the next 10 to 15 years.

An "old future" provides some perspective on the current debate over U.S. Army and U.S. Marine Corps "end strength" (Pentagonese for the number of active duty personnel authorized by Congress).

Let's return to 1990, just before Saddam invaded Kuwait. The U.S. Army had around 750,000 soldiers on active duty; the U.S. Marine Corps had 197,000 Marines. That same year, the U.S. population broke 250 million. Today, the U.S. population is slightly over 300 million.

That "old future" occurred during the final phases of the Cold War. Department of Defense budgeteers had already begun paring Cold War force structure. Though the Soviet Union hadn't officially dissolved, cost-cutters identified Cold War air wings and armored divisions as expensive legacies.

Desert Storm briefly delayed the planned decline in strength. Based on "the near-term future" the Defense and Congress envisioned, the United States didn't need Cold War troop levels.

However, by 1995, peacekeeping commitments began stressing the personnel system. Then, the United States entered the Balkans, and hasn't quite left yet.

The Army asked for a 30,000 troop "plus up" in the fiscal year 1997 budget request to meet those personnel requirements. It was denied.

The Clinton administration began using the reserves as an operational force rather than as a strategic, war-winning reserve. The Bush administration continued to do this after 9-11, nudging Army end strength from around 480,000 in 2001 to approximately 515,000 today. While that's arguably close to the 30,000 "missing" since 1996, it's a far cry from the forces on hand on Aug. 2, 1990, when Saddam's tanks were on the move. It's also proved to be inadequate to support Iraq, Afghanistan, peacekeeping operations and emergency contingencies. Continued...