The people have no authority to elect someone to violate the Constitution. If the prime minister of Canada said he was going to build a wall between his country and the USA and that Americans would pay for it, I know Americans would find that insulting. Mexico is also trading with the USA and Canada according to the terms of NAFTA, a treaty signed by the USA. By saying that the USA will not protect Poland from a Russian invasion because they are behind on their payment to NATO violates the treaty.
Not paying your payment also violates the treaty, but you either knew that and ignored it or you are simply ignorant.
Countries cannot always pay money when it is due. If the USA considers that a good reason for allowing the Russians to invade an ally, fair enough. We now know what the Americans think is important.
How many years are they behind in their payments?
All but four countries are behind in payments to NATO (Greece, UK, Estonia, and Poland).
Some member countries cannot afford to earmark 2% of their GDP for defense because they have pressing expenditures on caring for their aging populations. The baby boomers are entering the retirement now with insufficient young people and immigrants entering the work force. This cannot be helped overnight. European countries also have burdens on their tax revenues for medical care where everyone has coverage.
A problem is also the decision of NATO to benchmark the contributions to 2% of GDP because that figure fluctuates annually and some members who have factored for this percentage find themselves under the latest calculations for their economic performances. Some have paid the 2% previously but that contribution in real terms has since gone up. The contributions of 2% last year are under that mark this year even with no change in the actual amount paid.
Some countries may be small but strategically placed, such as Latvia and Lithuania which border Russia and these strategic locations are not factored into their contributions which undervalue their importance. Through NATO, the Americans can have strategically placed personnel and materiel right up against President Trump's friend, Vladimir Putin. These countries are a buffer against Russian aggression and benefit the USA which would have to pay a lot more if they disengage as Trump threatened and later find themselves with a bigger mess to repair in the future. The Americans currently have free bases all over Europe that money could not buy.
U.S. Naval Station in Rota, Spain