To answer the title question I call upon history:
Philistines
Ammorites
Greek / Hellenistic Empire
Roman Empire
Assyrian Empire
Nazi Germany
Ottoman Empire
All have raised their hands against the Jewish people / nation. All have collapsed and yet the Jews remain. Those that do not learn the lessons of history are doomed to repeat them.
Why protect Israel?
It was a global global decision recognizing a need to protect these people and sanctioned by the UN, a UN of the days gone by , not todays UN permeated and perverted by islam. It was a free western world decision which is in decline today due to islamic expansion.
A confusing statement considering that Israel did not even exist until 1948 ; if anything, America has declined since the 1950s.