It is absolutely in America's interest. For less than 0.01% of the defense budget, the USA can disarm Russia as a threat for another 50 years, if not forever.

The ROI looks pretty good:

1. Bolster NATO (Sweden and Finland have joined already)

2. Bolster the EU (Ukraine and Turkey gaining membership would be interesting)

3. Revive EU self-interest in not relying on US military and cash. This directly results in less foreign random wars because more parties are stakeholders.

4. Diplomatic leverage against China. They are actively supplying manufacturing capacity for weapons to the Russians.

5. Transparency around for who is supplying who with what regarding weapons and Russia. This makes it easier to sanction people/companies that do things that are Bad For Business globally.