Throughout history, even before it became a global superpower, the United States fought to defend the freedom of the seas. If Iran forces the US to accept an extortionary toll on the Strait of Hormuz, it will be a great blow to the US-led order that allows trade across international waters without heavy fees enforced by deadly power.
Control of the Strait gives Iran control over the price of oil. If they want the price higher, they let fewer ships through.
On one hand, Europe isn’t helping the US in the Strait with naval power because of Trump’s atrocious behavior toward Europe. On the other hand, Europe has let their navies so atrophy, that they have no ships to send!
Thanks to Trump repeatedly going back on deals, lying about deals, and pulling out of previous agreements, other countries can’t trust the United States. If a deal requires the US to actually follow through, especially if the other country has to give something first, then that deal is now unlikely because Trump can’t be trusted. This limits the possible deals the US can make.
Trump is ranting in fear of losing and of being Jimmy Carter and then talking tough. He’s acting like he’s losing it. He’s being left outside of the Situation Room because he’s so erratic that he may jeopardize missions.
In tough diplomacy, the world came together to prevent Iran from getting a nuke. Even Israeli intelligence said Iran was in compliance. Trump blew all that up by leaving the agreement unilaterally, claiming he could get a better deal. Instead, he gave us war.
The Obama-Iran deal set back Iranian nuclear development by over a decade, and was intended to be the start of negotiations and the relationship, not the final say. They hoped the next president, Hillary Clinton, could push deals forward. Instead, Trump was elected and took a different path.