But he warned against this tendency, saying that Israeli society's unwillingness to sacrifice some of its standard of living to acquire better defenses against less concrete and immediate threats could be destructive.
Israeli society's unwillingness to sacrifice some of its standard of living to acquire better defenses ultimately proved destructive. 
mnli hypothesis: Israeli society's unwillingness to sacrifice some of its standard of living to acquire better defenses ultimately proved destructive.  premise: But he warned against this tendency, saying that Israeli society's unwillingness to sacrifice some of its standard of living to acquire better defenses against less concrete and immediate threats could be destructive.