Hitler may have been insane (at least strategically), but even he could be deterred. And indeed, he was, for a brief, instructive moment.
The year was 1934. Hitler had been chancellor of Germany for 18 months and coveted Austria, his birthplace. So, the Nazi Party instigated a putsch to annex the land.
Nazis assassinated the Austrian chancellor, Engelbert Dollfuss, attempting to seize power. In total, they killed more than 100 people and injured several hundred others.