The 1973 War Powers Resolution allows a President to war on a nation with his sole executive authority for 60 days plus 30 days more for withdrawal. After that if the president and his military people have bungled the job and require more time Congressional authorization is required. I only point out the obvious fact since the media seems to want to obfuscate the plain legal facts of life that President Clinton and Obama have used for war in Bosnia and Libya.
Why a solid strike against Iranian targets requires more than 3 or 4 days is not plain. President Reagan made a couple of strikes against Libya that were effective as a deterrent. Punitive military strikes to discourage further opposition force aggression can be effective. Nothing is certain. Bunker-busting tiny nuclear ground-penetrating devices may be necessary to destroy Iranian enrichment facilities.
If President Trump is a peace monger that perceived weakness can encourage Iranian aggression such as may have occurred with the downing of a drone recently. The drone attack followed President Trump’s statement that the Iranian issue is a minor conflict; apparently they want him to regard it as substantive.