There is no need for President Trump to declare war. He can bomb Iran and use the Clinton Doctrine.
“”The cruise missiles strike on Iraq in June 1993 were ordered by U.S. President Bill Clinton as both a retaliation and a warning triggered by the attempted assassination by alleged Iraqi agents on former U.S. President George H. W. Bush while on a visit to Kuwait from 14–16 April 1993.[1]
He is doing everything under Pub. L. 107-40 (AUMF) It authorizes the use of United States Armed Forces against those responsible for the attacks on September 11, 2001 and any “associated forces”.
It’s also open-ended (NO expiration). Dems have been trying to repeal since Trump came into office.
https://www.congress.gov/107/plaws/publ40/PLAW-107publ40.pdf