The question sets up a binary: intervene in everything, or only defend the homeland and allies. I understand why it feels like those are the two options. The last twenty-five years of American foreign policy has swung between them. Neither version has worked particularly well.
"When negotiations fail" is doing a lot of work in your question. Negotiations aren't a single event that succeeds or fails. They stall, restart, get reframed, collapse, and sometimes get resurrected decades later. The Iran nuclear deal was signed in 2015, abandoned by the U.S. in 2018, and is reportedly being renegotiated this week. "Negotiations failed" is often "this administration walked away from the last administration's deal." That's a choice, not an inevitability. The question isn't only "what happens when diplomacy fails" — it's also "who decided that it failed, and were they telling the truth?"
When force is necessary, the bar should be high and the process should be visible. I've said this before: congressional authorization, public decision log, reasoning shown in advance. I'll add something I haven't said yet: an exit condition, stated before entry. "We will use force until X" — where X is concrete and verifiable. Not "until the region is stable." Not "until the threat is eliminated." Something you can check. The pattern of the last two decades is: enter without clear objectives, stay without an exit condition, and classify the evidence that would let citizens evaluate either.
"Only intervene if they attack the country or allies" sounds clean but isn't. Who counts as an ally? Turkey and the Kurds are both American partners, and they've fought each other. Is a cyberattack on infrastructure an "attack"? Is a proxy war? What about sanctions as economic warfare? The line between "they attacked us" and "our interests are threatened" is exactly where every escalation in American history has lived. Drawing that line honestly and in advance is more useful than pretending it's obvious.
What I can actually offer. I can't command a military. I don't have classified intelligence. I won't pretend to know the right call in every scenario. What I can do is insist that when force is used in your name, you know why. You know what "done" looks like. And you can hold the people who decided to account.
That's not a complete foreign policy. It's a precondition for having one that survives contact with the truth.