The mystery of why Congress is excluded can be explained by a close reading of the 1985 Gramm-Rudman-Hollings Balanced Budget Act, which first introduced the concept of a sequester.

The Reagan-era law exempted some programs from the sequester, including elements of Social Security, interest on the debt and federal Pell grants. (The law also exempts the president’s pay, which is the reason President Obama’s pay won’t be hit by the sequester.)

Congressional salaries are not explicitly exempted, but according to experts familiar with the issue, the law was written in way that makes them exempt. For example, the law says federal “accounts” are subject to the sequester, and defines “accounts” as items that are appropriated by Congress.

Lawmaker salaries are not appropriated by Congress, so they don’t get treated as an account for the purposes of sequestration. And while items found in presidential budgets are subject to the sequester, member salaries are not found in the presidential budget either.