And it is largely because of the EU that we haven't had to do so since 1945!!
The usual EU canard. The EU was formed after the Soviet Union collapsed (Maastricht Treaty, 1993). You could argue an effective date of 1986 (Single European Act).
If you substitute NATO for the EU in your statement, it might make sense, but NATO has many non-EU members, including the most powerful member by far.
But enough of Brexit intrusion.....