Isn't there a middle ground possible? For example, a guarantee, in law, that the US and Europe send military equipment to Ukraine if there is another war in the future?

USA could guarantee a deployment to European NATO countries large enough for them to be able to move much of their forced into Ukraine. And just guarantees on being able to buy armament would be useful. If there had been any ounce of political will something would have been possible.

No one is going to believe any guarantees now anyway, so it's a moot point. The US no longer has the goodwill capital for agreements, only transactions.

A guarantee would be pretty cheap. Not a lot actually needs to be done as long as people believe that this guarantee will be honored.

That is, if the US wasn't currently in the business of eroding trust in any and all agreements they may have entered.

Nah, it'd be as useless as Obama's "red line" in Syria.

For me it's an unfathomable stance.

A few years ago we kept making comparisons to Chamberlain appeasing to Hitler, inviting Hitler to keep expanding its territory at the expense of other sovereign nations in Europe, but at the same time made it very clear that Putin is no hitler and the comparison is too extreme.

Now it seems quite clear that the US under Trump is not willing to intervene in military fashion. For Russia, getting east-Ukraine in a year and waiting 3 years while ramping up its war economy to take the rest of Ukraine is a great outcome. For China, Taiwan is now a no-brainer as Trump declined to say whether he would intervene like Biden did. This is appeasement. Trump seems to want peace at any expense, he doesn't seem to recognize at all what the people of Ukraine have been willing to give their lives for, their country.

It's easy to have peace if you just surrender everything to a bully. Peace without justice is more like slavery. MLK said it right, there can't be peace without justice.