What are the potential implications of Trump's NATO exit for European security?

According to former Pentagon officer David Pyne, a Trump administration may consider completely exiting NATO and withdrawing U.S. security guarantees from countries opposing his policies on the Russia-Ukraine war. This move could significantly impact European security by potentially withdrawing American troops from the Baltics, leaving the continent vulnerable to Russian aggression. European officials are concerned that such actions would create a security vacuum that Russia could exploit, especially in regions like the Baltics. The withdrawal would undermine decades of transatlantic security cooperation and potentially embolden Russia to expand its influence across Eastern Europe.