Putin's Poor Excuse for occupying parts of Ukraine

To justify Russia occupying portions of Ukraine Putin has stated it's to protect Russian citizens.  So if we use the same logic then if any country's citizens are threatened outside of their borders then they would have the right to occupy the country that is threatening their citizens.   This is the same logic that Hitler used back in the 1930's when he started to annex areas next to Germany such as Austria for example.  World Leaders back then just let Hitler do whatever he wanted which eventually led to World War 2.  If World Leaders just let Putin do whatever he wants this could lead to major problems down the road.