While U.S. Sen. Claire McCaskill was in St. Louis on Wednesday, she and other members of the state’s congressional delegation — in both parties — also cosigned a letter to federal officials in the IRS and the Social Security Administration, challenging their new interpretation of which state education workers must pay Social Security along with making payments into the state’s teacher retirement program.

In an e-release Thursday, the signers said they “joined together this week to standup for Missouri educators” and had challenged federal officials during a Dec. 12 meeting in Washington.

At that meeting, the Missouri members of Congress said, “federal government officials were unable to answer the lawmakers’ questions about how a clarification to a federal rule will affect the retirement benefits of Missouri public school professionals…”

As a result, the delegation “asked the agencies to push back indefinitely their deadline for implementing the regulation.”

Here’s the issue, as the delegation sees it:

The clarification of the rule, currently set to take affect on July 1, 2009, will mean that some public school employees can no longer pay into Missouri ’s popular Public School Retirement System in lieu of Social Security. They instead will have to pay into both while receiving fewer benefits

“We request that the agencies take no further enforcement actions until these questions are adequately answered and sufficient clarity is provided to the school districts and employees,” the delegation wrote in their letter.

The cosigners were: McCaskill, D-Mo., U.S. Sen. Christopher “Kit” Bond, R-Mo., and U.S. Reps. Ike Skelton, D-Lexington, Jo Ann Emerson, R-Cape Girardeau, Roy Blunt, R-Strafford, Todd Akin, R-Town and Country, William Lacy Clay, D-St. Louis, Sam Graves, R-Tarkio, Russ Carnahan, D-St. Louis and Emanuel Cleaver, II, D-Kansas City.