1 - The U.S. military is overstretched. It is engaged in the fight against the Islamic State group in the Middle East. It is also trying to prevent terrorist attacks at home and abroad. And the row with Russia over Ukraine continues.
2 - U.S. military forces are weary. Many U.S. troops are suffering from post-traumatic stress disorder as a result of their tours of duty in Afghanistan and Iraq. The mental condition brings back vivid memories of combat, makes sleeping difficult and changes how sufferers react to those around them and to the outside world. It is incurable. Apparently this is holding back U.S. President Barack Obama from sending ground troops to Syria.
3- Finances. The federal government is being forced to spread its dollars thin, and the defense budget is getting squeezed.
It will probably take about 10 years for the battle-fatigued U.S. military to revamp its capabilities to a point where it would feel comfortable rivaling China. In 10 years, it will have replenished its ranks and deployed new arsenals. In the meantime, it will have to try its best to contain contingencies with its existing resources.
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