Monitoring campaign finance is like defending a fort: You always have to be on the lookout for a sneak attack. The latest shenanigan by incumbent politicians for whom campaign money is like oxygen comes in the form of a rider that would loosen restrictions on a type of campaign fund for U.S. senators known as their leadership PAC.

Rather than being introduced on its own merits, the change was snuck into the transportation appropriations bill during a subcommittee markup.

Currently, senators are barred from spending any contributions to their leadership PACs on political campaigns. The rider would allow them to donate money from their leadership PACs to the national party committee -- which can then turn around and give it back to the member to use in a campaign. It would effectively increase an individual's maximum contribution to a candidate from $4,200 to $34,200 over the course of a six-year campaign -- an eight-fold jump.

The rider is sneaky, underhanded and dishonest. It's also patently unfair to challengers, whose contributors would still be held to the $4,200 limit.

Sens. John McCain, R-Ariz., and Russ Feingold, D-Wisc., are planning to introduce an amendment this week to strip the rider from the bill, forcing debate on this issue out in the open.

At that time, any senator with the guts to actually defend this unfair campaign practice can stand up and say so. We urge the others, particularly Sens. Arlen Specter and Rick Santorum, to vote for the amendment to eliminate this loophole.