Israeli security forces are on maximum alert today, the eve of the evacuation of 21 Jewish settlements in the Gaza Strip and four more in the West Bank. Roadblocks have been set up in southern Israel to prevent pullout opponents from complicating matters. Extra checks are also in place in Jerusalem where devote Jews have been flocking to the Wailing Wall. The Jewish fast of Tisha B’Av began at sunset yesterday.It is a 24-hour period of mourning for the many tragedies that have occured to the Jewish people on this day over the centuries. They include the destruction of the first and second temples, the expulsion of Jews from Spain and the beginning of events leading to the Holocaust. For many Jews, the giving up of the settlements is one more calamity to add to the Tisha B’Av list.