Joining Democratic presidential rivals Hillary Clinton and Barack Obama, GOP presidential heir apparent Sen. John McCain this week issued his own unexpected endorsement of Rep. Mike Pence's proposed federal shield law -- an endorsement that carries all the more weight not just because of the likelihood Sen. McCain will be the next president, but also because of his known "hard line" on national security.

Rep. Pence, R-Ind., has been pushing his current federal shield law for three years. It passed the House overwhelmingly in October, and a shield bill has also cleared the Senate Judiciary Committee. But the proposal has been kept off the Senate floor by vigorous opposition from Senate Republican Whip Jon Kyl, Sen. McCain's junior colleague from Arizona.

THE push for a federal shield law to help journalists protect the identities of confidential sources got a big boost last week when John McCain, the Republican presidential candidate, endorsed it in Washington at a convention of the nation’s newspaper editors and publishers.

The Democratic candidates, Hillary Clinton and Barack Obama, are also on board, and supporters of the proposal, which is strongly opposed by the Bush administration, are optimistic that success is near. The bill awaits Senate action after the House passed its version last October by a vote of 398 to 21...

There are two competing interests here: the right of an individual who believes he has been wronged to sue for damages, and a reporter’s need to keep promises of confidentiality to sources who provide information for stories of vital public interest. If something close to the House version of the shield law were to become reality and be applied to this case, Locy would be off the hook, because the reporter’s privilege in most civil cases like Hatfill’s would be absolute. But the Senate might include a balancing test — to let a judge decide which interest was more compelling in each case — meaning Locy could still be in hot water. Walton said he thinks government employees should be fired for talking about a criminal investigation...