If the government shuts down on October 1st-- or any other time-- it is generally accepted that Senators and Representatives will still get paid, because of the wording of the Twenty Seventh Amendment, which reads, “No law, varying the compensation for the services of the Senators and Representatives, shall take effect, until an election of representatives shall have intervened.”
Simply put, this means that if Congress passes a pay increase for itself, the representatives can’t take advantage of it unless we’ve re-elected them. Sounds good, right? But unfortunately, it also applies to decreases in their pay.
The history of this Amendment is interesting. It was part of the twelve amendments proposed in 1789, ten of which were ratified within two years and became the Bill of Rights. But two of them-- one dealing with the number of voters each Member of Congress would represent, and the other dealing with congressional pay, were not.
Compensation for Constitutional offices is addressed in two places in the Constitution. Article II, section 1, says that the President’s pay cannot be increased or reduced during his time in office. Article III says that the salaries of federal judges cannot be decreased during their time on the bench (and since most serve for life, that means they are guaranteed at least their starting salary). It does not say their compensation can’t be increased, though-- which really doesn’t pose the problem of a “hand in the till,” because they don’t participate in the creation of legislation that would increase their salaries.
But the Constitution itself says only of the Senators and Representatives that they “shall receive a Compensation for their Services, to be ascertained by law, and paid out of the Treasury of the United States” (Article I, Section 6.) They were free to increase their own compensation at will, and did so.
As so often happens in America, people began muttering that “there ought to be a law” preventing this, so when they realized that there actually was a proposed amendment on this subject that had been kicking around for two hundred years, enough states ratified it and it became the Twenty Seventh Amendment on May 7th, 1992.
As with so many laws, the intent was a good one-- that sitting members of Congress would not be able to vote themselves a raise and take advantage of it. The people, by way of an election, could intervene, and send someone else to reap the benefits of that increase.
The wording is interesting, though. The Constitution says that the current Congress can’t vote themselves a decrease in pay that will take effect until after the 2014 elections. But they aren’t actually voting to stop paying the government’s bills-- the problem with the threatened government shutdown is that they are not voting to fund the government.
That poses an interesting legal question-- could their checks be held like everyone else’s, and delayed until the money is there? If a government shut down is based on a current law (passed since January 2nd of this year) that designates who will get paid and who will not (“essential employees”), then they will continue to be paid. But if there is no law passed during the current Congress dealing with this, then Congressional paychecks-- along with all the others-- shouldn’t be issued until after they have funded the federal government. Payments can, of course, be issued retroactively, once they fund the government-- but failure to issue a check on insufficient funds in the Treasury is technically not the same as decreasing a salary.