It’s hard to think of anything more critical these days than information about terrorists, and a bill on Gov. Paterson’s desk would help keep it flowing. The Libel Terrorism Protection Act basically would make authors immune to defamation suits in countries that don’t offer the full free-speech rights provided by the US and New York constitutions. Paterson has until tomorrow to sign the bill – and he shouldn’t hesitate. The need for legislation became clear when Saudi businessman Khalid bin Mahfouz won a UK libel judgment against Manhattan author Rachel Ehrenfeld. In a recent book, she named Mahfouz as a funder of terror. He denies it – and won a judgment against her under the low British standards for libel. New York courts then said that a law would be needed to block enforcement of the judgment here. The law would extend speech and press protection on a range of issues – and ensure that critical research can’t be blocked by foreign courts. And that may prove critical, as US success in the War on Terror continues to rely on the free flow of information.