It’s long overdue, say experts. And naturally, it’s already over budget.

But can we afford not to prevent this Great Lakes reconquista?

The voracious carp, which can grow to 50 pounds, are within 50 miles of the lake, and the only thing stopping them from completing the journey is an underwater “electric fence,” which the U.S. Army Corps of Engineers constructed under the canal. It was activated in 2002 — the first such barrier ever installed in a navigable waterway…

The Corps is planning to replace the original barrier with a new, more powerful one capable of lasting at least 20 years, but that project is in limbo because of funding shortfalls and safety concerns…

To finish the job … the Corps needs an estimated $6.9 million beyond the original $9.1 million price tag. The funding is included in the Water Resources Development Act, which is in the hands of a congressional conference committee.

Joel Brammeier, associate director of the Alliance for the Great Lakes, said congressional action to finish the barrier is desperately needed, but it is already too little, too late.

“This should have been built and turned on years ago, but it’s still a temporary solution to a permanent problem,” he said.

Bush is proposing a “virtual carp fence” involving hundreds of Carp Patrol Agents to monitor the fish’s movement. Tune in tonight to “The O’Reilly Factor” when Bill will debate the subject with noted pro-carp advocate Geraldo Rivera, who says he’s “stricken” by public support for the fence and regards carp eaters as “no better than camp guards at Auschwitz, really.”