It will not happen until Article 5 has been undermined. That is the condition. What dictates "undermined" is purely up to Putin and his Oligarchs. They could be wrong or misled, but I am telling you that for as long as the US maintains NATO's integrity and perception, Russia will not invade. 100%.

Putin said himself that it would be stupid to start a war with NATO. The only scenario where a war occurs is one where Article 5 has been undermined, and that is largely Russia's strategic goal. Every Russian politician knows a war with NATO is out of the question otherwise.

I don't really see that. Russia would surely be incapable of taking on Poland, but realistically it ends with Russia's own tanks marching to Moscow.

Argue against providing funding to DHS then, not that they quit doing their job in individual instances. They've already been funded to perform this duty, if they sit around and do nothing the tax money simply goes to the void.

"Their own interests" is 70,000 American citizens. This is explicitly DHS' purpose.