It explains that when the original TRIA legislation was passed by the House in 2001, it contained mandatory and full payback of any federal monetary assistance extended to the insurance industry as a result of a large-scale terrorist attack. "This provision was weakened in conference with the Senate, which instead insisted on conditional payback at the discretion of the Treasury secretary," the letter said.

The bill "is the only legislative proposal pending that would provide for full, mandatory taxpayer reimbursement for federal assistance granted to the insurance industry, while significantly raising deductibles and co-shares over current program levels."

By contrast, the Senate bill, S. 467, maintains conditional payback, which in the event of another terrorist attack would leave the Treasury and taxpayer exposed to permanent monetary loss, the letter said. "The House bill eliminates this possibility," the letter said.

The letter concludes by saying that, "Keeping the insurance industry liquid and solvent in the event of a terrorist attack is vital to the U.S. economy.

"However, equally important is ensuring that already overburdened U.S. taxpayers do not bear the additional load of providing this protection. I urge you to strongly support H.R. 4314, the most fiscally responsible terrorism insurance bill currently pending."