i think you should review the US strategy in the middle east. its not to conquer every single state that are not willing to suck its you know what, but to achieve a balance of power and regional stability so that oil can be drilled and enter the market without restraint. what is invading iran gonna do? holmutz strait will be sealed, oil price is gonna sky rocket, how does that benefit the US?
by any measure israel in a hostile stance is NOT in line with US interest. they have been getting away with this thusfar is largely because of the israel lobby, such as AIPAC. washington hates it when israel cross the line, it puts them in a really awkward spot, and most of all it undermines regional stability.
US policy on the Middle East is not as clean cut as you believe. There are competing factions consisting of people and ideas in the US. Key words for you to learn: war hawks, chicken hawks, and doves. Read about the US support of the Shah of Iran, who temporarily overthrew a democratically elected government. Then the US pro-peace faction won the debate and the US backed out of installing a puppet government in Iran.
Then there was President Bush, who wanted at least 3 aircraft carriers near Iran, and various reports from the government and corporate media recommended an invasion of Iran. Thankfully, the US pro-peace faction won, so the Iranian invasion was called off. This cost the job of Admiral Fallon (that's my take), because he publicly rejected the Bush Administration's crazy invasion plans of Iran (then he publicly claimed this never happened).
President Bush sent Israel lots of weapons before or during the horrific war crimes against Gaza. I believe Italy, Greece, or some European nation refused to help the US transport these weapons. Many US congressman (FYI, a part of Washington) and their allies were against the additional weapons aid for Israel. Nonetheless, the Bush Administration (FYI, a part of Washington) and its allies thoroughly supported Israel's infamous attacks.
If not for China, Russia, the minority European doves, and the minority US doves, the US and European governments would have sanctioned Iran (which primarily trades with China and Germany). FYI, sanctions are euphemisms for economic warfare. Once Iran fights against the sanctions, the US chicken hawks and war hawks will claim the US needs to invade Iran to enforce the sanctions or to rebuild Iran.
This is only basic information. It's not hard to learn more.
The world (including US politics) isn't always black and white. Many times, it's some shade of gray.