Quill Lawrence

And the costs so far for the U.S.

have been political and economic.

And putting boots on Iranian soil would bring much higher risks of U.S.

casualties and bring in a whole other set of variables.

And war is unpredictable.

And the main economic pain point for the U.S.

is the Strait of Hormuz, which remains largely closed, choking off oil and other crucial exports.

and driving up prices worldwide, including at the gas pump here in the United States, it's not clear how these extra troops would affect that Iranian blockade or what countermeasures Iran might take.

Two to three thousand troops from the 82nd Airborne, based in Fort Bragg, North Carolina, have received written orders to deploy to the Middle East, according to a U.S.

government official who is not authorized to speak publicly.

The soldiers will come from the division's immediate response force, which is able to mobilize worldwide within 18 hours to do a variety of missions.

Along with two Marine Expeditionary Units already sailing toward the Persian Gulf, this could bring about 6,000 to 8,000 American ground troops in close proximity to Iran.

President Trump has alternately said he would not put boots on the ground and that he won't rule it out.

Quill Lawrence, NPR News.

The USS Boxer group of three ships carrying thousands of Marines from the 11th Marine Expeditionary Unit has left California and will take about three weeks to reach the Gulf, according to two U.S.

officials who were not authorized to speak publicly.

That's in addition to the USS Tripoli group, with more than 2,000 Marines, expected to arrive soon from Japan.

CENTCOM would not comment on the deployment or its mission, but Marines are traditionally ground troops.

Quill Lawrence, NPR News.

U.S.