Don't you think maybe, under the circumstances, this ought to be left up to the troops themselves? Don't order them in but if they want to volunteer to go in and help let them?

CNBC:

U.S. forces kept 50 miles away from Japan nuke plant

WASHINGTON - U.S. forces in Japan are not allowed within 50 miles of Japan's crippled nuclear power plant, the Pentagon on Wednesday, explaining measures meant to keep troops safe during a relief operation.

The U.S. military is also giving some flight crews potassium iodide tablets ahead of missions as a way to guard against effects of radiation, officials said.

The measures were seen as precautions and the Pentagon said no U.S. forces have shown signs of radiation poisoning.