My first thought was of the rivalry in the 2nd half of 19th century between William Gladstone and Benjamin Disraeli. Gladstone led the Liberal party (in the final decades of ‘liberal’ describing laissez faire) while Disraeli founded the modern Conservative party at a time that conservative referred to maintaining state power.
In Prussia/Germany I think about Eugen Richter vs. Otto von Bismarck. http://bastiat.mises.org/2012/03/the-ron-paul-of-the-second-reich/
I know these examples are a bit more about liberalism vs. collectivism than liberalism vs. European integration…. I’ll try and think of better examples.
*Edit* and I just reread your question and realize that you’re looking for 1950s and forward… So I didn’t help. I’ll keep looking.