In the days since the Jan. 3 drone strike that took out Iranian military leader Maj. Gen. Qasem Soleimani, roughly 9,000 conventional troops have been deployed to the Middle East, ranging from Marines on amphibious ships to Army Rangers and paratroopers.
On the home front, some of the military’s most deployable units are holding steady ahead of any orders.
Another brigade of paratroopers at Fort Bragg, North Carolina, is assuming the Immediate Response Force mission as the last of the 82nd Airborne Division's 1st Brigade Combat Team launches on its emergency deployment to the Middle East.
The United States may be on the brink of hot conflict with Iran but, for now, the remaining three infantry divisions in the XVIII Airborne Corps are not preparing for rapid deployment missions, according to corps officials.
The U.S. Army has many types of conventional combat units, but the XVIII Airborne Corps is specifically designed to handle crisis situations similar to the chain of violent events last week that ignited the possibility of a conflict with Iran.
"By virtue of being in the XVIII Airborne Corps, we are always a little bit more aware of what is going on; we do have that [short-notice] mission," Col. Tage Rainsford said. "We are the corps-equivalent of what the 82nd Airborne is if you look at the corps of the Army. The XVIII Airborne Corps would be the quick-reaction corps."
That capability was demonstrated just one week ago when the 82nd's 2nd Battalion, 504th Parachute Infantry Regiment, alerted and began boarding planes for Kuwait after mobs of Iranian-backed militia members stormed the U.S. Embassy compound in Baghdad.
Just days later, the Iranian government began threatening military retaliation in response to the strike that killed Soleimani, head of the Islamic Revolutionary Guard's elite Quds Force, in Baghdad.
The Pentagon ordered an assortment of rapid-deployment forces to the region, including another 3,000 paratroopers from the 504th PIR; the three-ship Bataan Amphibious Ready Group, which carries 4,500 Marines and sailors; and an element of the 173rd Airborne Brigade, which is based out of Vicenza, Italy.
Army Special Operations Command is also deploying a company-sized element of the 75th Ranger Regiment with other special-operations forces.
The XVIII Airborne also has the 101st Airborne Division (Air Assault), based at Fort Campbell, Kentucky; the 10th Mountain Division (Light), based at Fort Drum, New York; and the heavier 3rd Infantry Division, located at Fort Stewart, Georgia, under its command.
These divisions do not have the same short-notice mission as the 82nd, but it's not unusual for them to be expected to deploy rapidly.
Elements of the 101st and 10th Mountain were launched into Afghanistan shortly after terrorists attacked the U.S. on Sept. 11, 2001, well before the 82nd Airborne deployed.
In 1994, the 10th Mountain formed a large part of the Multinational Force Haiti during Operation Uphold Democracy to restore order after a military coup and help reestablish the government under Haitian President Jean-Bertrand Aristide.
"As a whole, we are more prepared to deploy rapidly, and that is kind of what we train for. And we are able to do that because we are primarily a light organization," Rainsford said.
For now, however, the 10th Mountain and the 101st have received no guidance to prepare for rapid deployment operations.
"It's steady-state training operations for us," 10th Mountain Lt. Col. Kamil Sztalkoper told Military.com.
The division's 1st Brigade Combat Team, as well as its combat aviation brigade, have been deployed on a scheduled mission in Afghanistan.
Lt. Col. Patrick Husted, spokesman for 3rd Infantry, had a similar answer.
"Nothing has changed for us," he told Military.com.
Special Operations Command typically does not announce deployments. The biggest direct-action hammer in SOCOM's toolbox is the 75th Ranger Regiment, a highly specialized raid force made up of 1st Ranger Battalion at Hunter Army Airfield in Savannah, Georgia; 2nd Ranger Battalion at Joint Base Lewis McChord, Washington; and 3rd Ranger Battalion at Fort Benning, Georgia.
Because of the regiment's size and truly elite operators, Ranger units typically do not deploy to locations and sit in reserve for extended periods of time.
Outside the continental U.S., the Army's 173rd Airborne Brigade serves as the rapid response force in Europe.
On Monday, units from the 173rd deployed to the Middle East, according to a statement from U.S. Army Europe.
"We can confirm that elements of the 173rd Airborne Brigade deployed 6 Jan. to bolster security, for force protection and to be prepared for any contingency," according to the statement.
Meanwhile, the 82nd Airborne will continue to maintain a ready brigade for the Immediate Response Force mission, even though its 1st BCT is deploying to the Middle East and its 3rd BCT is in the middle of a deployment in Afghanistan, according to 82nd spokesman Lt. Col. Mike Burns.
Currently, the unit's 2nd BCT will be the only infantry unit left at Bragg, but Burns said he was unable to be specific about which BCT that would assume the IRF mission.
"Another brigade in the 82nd would step up to fill that IRF role," he said.
-- Matthew Cox can be reached at firstname.lastname@example.org.