"Be neutral, don't take sides".

At the start of World war I, USA was neutral.

Germany sunk several commercial and passenger vessels, including some U.S. ships. Protests were held over the sinking of an ocean liner traveling from New York to Liverpool, England with hundreds of American passengers on board.

Germany sunk four more U.S. merchant ships the following month, and on April 2 Woodrow Wilson appeared before Congress and called for a declaration of war against Germany.

Also in World war II, many countries were neutral. Some of the countries that declared their neutrality were later invaded.

Denmark and Norway were neutral but both were invaded by Nazi Germany on April 9th, 1940.

USA was neutral until Japan attacked Pearl Harbor. This attack made USA to join the war.

The enemy doesn't care if you are neutral or not. Neutrality doesn't give you an immunity from being attacked.