In political discourse, the term terrorism is far more useful when it remains undefined- for throughout decades it has been manipulated and molded to delegitimize the opposition. The guilty "terrorist" may change but the aim remains the same.
Allow powers in the region to compete and balance against each other. When that fails, intervene with as little force and risk as possible. For example, the conflict between Iran and Iraq canceled out two rising powers until the war ended. Then Iraq invaded Kuwait and threatened to overturn the balance of power in the region. The result was Desert Storm.
Eviction of the Iranian regime from Iraq, specifically prohibiting the supply of any further military and arms to Iraq, in clear violation of UN resolutions.
Delivery of the Su-25 aircraft, which American officials said had already conducted missions in western and northern Iraq, is the latest step Iran has taken