When a metzora (leper) gets tzaraas (leprosy) which covers his entire skin, he is pronounced pure. This seems to be a great irony, as he is completely affected by the spiritual ailment. However, this concept applies to the end of days as well. When the government has completely turned to heresy, Moshiach will be able to arrive. Although it seems to be completely bad, the clear clarity of what is right and wrong can herald the arrival of Moshiach, and a completely new world order.