1.   Critics say laws originally set up to benefit workers now provide an almost impenetrable shield for employers.

2.   It did not promise an impenetrable shield.

3.   Over decades of protecting Israeli leaders, the Shin Bet secret service had built a reputation as a nearly impenetrable shield.

4.   The first is that missile defense consists exclusively of building an impenetrable shield against intercontinental missiles carrying nuclear warheads.

5.   They want the high priests of the government to provide them with an impenetrable legal shield against all of their enemies for all time.

6.   While improvements are unquestionable, many regulators and industry officials say, the real goal of erecting an impenetrable shield against weapons and bombs remains distant.