BY WESLEY P. HESTER

A day after officially endorsing Republican U.S. Senate candidate George Allen, the U.S. Chamber of Commerce is launching an effort attacking his rival, Timothy M. Kaine.

The new “voter education and grassroots campaign” will “highlight Tim Kaine’s record on government overreach and its negative impact on Virginia’s economy.” Most notably, the effort will feature a TV advertising blitz, the first ad of which was released today.

In announcing the effort, Rob Engstrom, the U.S. Chamber’s senior vice president and national political director, commented that “free enterprise, not more government, will lead the American recovery.”

He added: “In today’s economy we cannot afford another anti-business vote like Tim Kaine in the U.S. Senate.”

The group’s train-themed first ad blasts Kaine’s record as governor, support for the president’s health care reform law and says, “As senator, Tim Kaine would derail Virginia’s recovery.”

Kaine campaign spokeswoman Brandi Hoffine responded by vigorously defending Kaine’s record.

“As governor, Tim Kaine helped guide Virginia through the worst recession since the Great Depression,” she said. “He cut $5 billion, including his own pay, and balanced Virginia’s budget all four years.”

Hoffine said Allen “has admitted he helped create our economic mess during his first term in the Senate and has offered no new ideas to fix it.  That’s a pretty clear choice.”