We've all seen this phrase in block letters: "REPORT SUSPICIOUS ACTIVITY," followed by a 1-800 number. But if a House Democrat manages to kill a tipster-immunity measure under consideration in Congress this month, people who report suspicious behavior could be sued in civil court if the accused are not charged with a crime. November's frightened U.S. Airways "John Doe" passengers in Minneapolis are already in the crosshairs. 

    The lawmaker in question is Bennie Thompson, chairman of the House Homeland Security Committee. He thinks that granting tipsters immunity amounts to racial and religious profiling. Yes, that's the Democrats' "homeland security" pointman in the House speaking. 

    For two months, Mr. Thompson has deployed the profiling argument against this measure, tucked into the House transportation-security bill. The good news is that a bipartisan House majority already passed it 304-121 seven weeks ago. But sadly, Mr. Thompson is expected to strip it from the bill. He is expected to be the lead House negotiator in the coming weeks when the bill reaches conference committee, and if he is, he will have considerable sway over the final product.