We previously went through some plausible escalation scenarios in the event President Trump orders military strikes on Iran. The problem with a supposedly 'limited' attack is that Tehran's response could be devastating, targeting American military bases across the region. This would then turn into all-out war in the region.

Iran has every interest in establishing deterrence quickly, in order to get the US administration and its allies second-guessing the pursuit of full regime change, which would probably require ground forces and not just an aerial bombardment operation.

With the countdown ticking toward some level of military operations, and even as US officials claim diplomacy is still happening, it appears the Pentagon is taking drastic actions and precaution - ordering the evacuation of some 'exposed' Gulf bases. However, Fox's Pentagon correspondent has cited US officials who deny this is happening - but the officials might simply be running cover.

The NY Times reports Friday that "Hundreds of troops have now been evacuated from Al Udeid base in Qatar, Pentagon officials said, and there have been evacuations at the cluster of U.S. bases in Bahrain that house the Navy’s 5th Fleet."

There could be more such evacuations or at least personnel reductions to come, as "There are also American troops at bases in Iraq, Syria, Kuwait, Saudi Arabia, Jordan and the United Arab Emirates," the same report notes.

It must be remembered that Iran launched a "devastating and powerful" missile attack on the Al Udeid last June, in retaliation for the 12-day Israeli assault, and US bombing campaign of Iranian nuclear sites.

US military planners are concerned even by how close the two US carriers in the region get to Iran's feared ballistic missiles:

A second American military official said that U.S. Central Command is keeping two aircraft carriers deployed in the Middle East at a considerable distance from Iran, to protect them from becoming a target.

Officials also noted that it was difficult to hit an aircraft carrier traveling at speed with a ballistic missile. In addition, the carriers are escorted by destroyers, which have the ability to shoot down ballistic missiles.

There's also the possibility that Iran could send drone swarms on US locations in the event of an unprovoked attack. The last several years have seen small drones get better and more effective at evading sophisticated anti-air defenses, though these often have a more limited range.

Fox says there's contradictory reports and that the NYT Times claims are false...

Iran this week stated to the United Nations in a formal letter that the Islamic Republic "will not initiate any war" while stressing that the United States would bear "full and direct responsibility for all the unforeseen and uncontrollable consequences" resulting from an attack against it.

The letter, issued Thursday, spelled out that US bases, facilities, and assets would be Iran's "legitimate targets" if the US follows through on its threats. So it seems Pentagon decision-makers are taking this seriously, and are now likely moving at least some US personnel out of harm's way.