I put all my money on my bet here: the US won't dare to attack Iran. The reason is quite simply and quite clear. Times has changed, and we are now in a multi-polar world. .
At the time of Iraq wars, China was still aligned with the US against the USSR, while the USSR was in the process of disintegration due mainly to its own failures. The US then was a true unrivaled superpower and Iraq was a true international orphan. This is why the US - Iraq wars could be unfolded like a reality TV show of "SWAT storms a civilian house" to the audience world-wide. The Iraq wars certainly inflated, and are still inflating Washington hawks' confidence at America's ability to wage wars overseas.
Now, the Trump admin. has declared China and Russia are America's national security adversaries. China has a de facto alliance treaty with Russia. This Sino-Russia treaty states clearly that any issues involving any of the two signatories' national security warrant both countries to co-operate, and that the two countries are dedicated to safe-guard of world peace.
Trump has soured America's relations with China and Russia simultaneously. China and Russia have every reason to find any opportunity to faithfully carry out their duties as an America's strategic adversary. If the US ever dare to touch Iran, or any other countries that the two countries regard as their friends for this matter, China and Russia will immediately act jointly to punish the US, and the consequences will be dire and deadly for the Americans. A war led by the US in Russia's neighborhood certainly is an issue threatening Russia's national security. The two signatories of Sino-Russia treaty will act accordingly. And another Vietnam war-like catastrophe is waiting for the US.
Doesn't Trump know this? You'd better bet he surely does. Then why did Trump provoke Iran so much that he even sent a lot of military assets to the Gulf? Well, he's such an overconfident guy that he always over-counts his own cards and under-counts other people's hands. He thinks he can out-fox other people with high-pressure sale techniques. But his Fart of the Deal gives him more trouble than success. His NK gamble was already ended in his disgrace. He can't afford another disaster before his 2020 re-election campaign officially starts. This is why his golf-boy Abe, Japan's PM, has to rush to Tehran, trying to help him find a face-saving exit from his Iran gamble.
Lesson from Trump's failures: don't gamble if you can't afford to lose.