There's no doubt the Trump Administration has long had a target for Iran. The Islamic Republic, for its part, makes it an easy antagonist for the United States. Now, the U.S. is taking the war of words one step further by designating the country's Revolutionary Guard Corps as a foreign terrorist organization.
While many groups are labeled as foreign terrorists by the United States, the IRGC is the first official military apparatus of an internationally recognized country to be labeled as such. Now what does that mean for the Revolutionary Guards and for Iran?
The United States and Iran have not been friends since the Islamic Revolution of 1979 ousted the Shah and installed the Islamic Republic – who allowed American citizens to be held hostage for 444 days. Ever since, the two powers have always stopped just short of an outright shooting war, choosing instead to cause malicious harm to one another behind the scenes. Iran provided material support and outright aid to insurgent groups fighting the U.S. military during the 2003-2011 Iraq War while the United States has consistently backed anti-Iranian operations throughout the region for decades. Labeling Iran's Revolutionary Guards as a terrorist organization changes the game a little.
The Revolutionary Guards are a unit intended to defend the Iranian government, not just its borders; and its mandate extends to anywhere in the world that could pose a threat to the Ayatollah and his system of government. Its main concern isn't limited to potential invaders, the IRGC will go after any group or person who poses a legitimate threat to Iran, traditionally through any means necessary.
Iranian soldiers in Iraq.
As of April 8, 2019, the Trump Administration has designated the IRGC as a foreign terrorist organization. Now the IRGC is subject to a slew of financial restrictions that must be followed by citizens of the United States, and the move will pressure U.S. allies to follow suit. Americans and American companies cannot knowingly provide material support to institutions that might support the IRGC, specifically "currency or monetary instruments or financial securities, financial services, lodging, training, expert advice or assistance, safehouses, false documentation or identification, communications equipment, facilities, weapons, lethal substances, explosives, personnel, transportation, and other physical assets, except medicine or religious materials."
Revolutionary Guards members and people related to them can also be removed from the United States and any company holding IRGC assets must now retain them and report them to the Office of Foreign Assets Control. More importantly, this gives the U.S. more combat options under the most recent authorization for the use of military force.
IRGC Commander Qasam Soleimani with Iraqi troops fighting ISIS in Iraq.
The United States has been operating on the post-9/11 AUMF passed by Congress since 2001. In that time, the AUMF has allowed the military to deploy to more than 150 countries in support of anti-terror operations, including Iraq, Afghanistan, Libya, Syria, and elsewhere. If the Trump Administration tries to extend the AUMF to Iran's Revolutionary Guards, it could be tantamount to using the full force of the U.S. military against known IRGC units anywhere, under the 2001 AUMF.
Basically, all the President has to do to get the funds to invade Iran is to make a compelling argument that it's harboring al-Qaeda. Which, to be clear, it is not. The brand of Islam espoused by al-Qaeda, and the brand taught by the mullahs in Iran have been at each others' throats for centuries – so that argument would have to be incredibly compelling.