That is ridiculous.
Manifest Destiny violated hundreds of US treaties.
The natives had legal rights that we not only violated, but then deliberately committed genocide.
The Monroe Doctrine was the illegal theft of Spanish and Portuguese colonies, where we treated the native worse than they did.
There is not a single war of invasion the US ever did that was remotely "legal".
For example, there is nothing remotely illegal about Noreiga dealing drugs if he wants to.
The US medical students in Grenada did not want our invasion, and it was our invasion that endangered them.
The invasion of Vietnam violated the UN charter, as well as the Paris Peace Accord between the French and Vietnamese.
All US invasions have been illegal since 1945 when the UN charter was ratified into US law.
The US put nukes in Poland around 2012. The Sprite nukes were originally built for ABM, but are now just medium range nuclear attack purposes.