You should have stopped after the first "NATO." If you think the US will immediately send soldiers to die in Lviv if Poland sends in forces, you've got another think coming.

The endlessly-cited "Article 5" protection does NOT say that other NATO countries will automatically go to war if another NATO country is attacked. Every country retains its autonomy.

You can bet your bottom dollar the US will do everything possible NOT to send our troops to fight. Exactly as we are doing now.