Kudos to the S.C. Senate for amending its rules to make it easier to end filibusters, make it harder for a single senator to stop consideration of a measure and prevent last-minute amendments on the third reading of a bill.

The practice of adding last-minute amendments resulted last session in a Frankensteined bill called the Life Sciences Act, which at the last minute was amended to cover such diverse topics as eminent domain for state colleges, a tourism center for Myrtle Beach and the possibility of a third law school — all in violation of the state constitutional requirement that each bill address only one subject.

Although the new rules are a good start, proponents of legislative accountability should not let down their guard. One Republican senator was reported in the news as noting that “I’ve done found ways to get around this; you betcha there’s some tricks,” and “the rules that we passed can be circumvented.”

Instead, the citizens of South Carolina and the other branches of government that provide necessary checks and balances need to remain vigilant against what James Madison described as a legislature’s tendency for “drawing all power into its impetuous vortex.”

The significant checks and balances on legislative logrolling include the power (and duty) of the courts to declare such legislative acts unconstitutional, and the governor’s veto.

Because the governor does not have a line-item veto on most bills, this constitutional check is often defeated by bobtailing pork-barrel or unpopular legislation onto popular legislation and daring the governor to veto the entire measure (as happened with the Life Sciences Act, when Sen. Phil Leventis convinced the Senate to add a provision to make USC Sumter a four-year university). Such dare tactics rely on the fact that, in this situation, most governors would chose expedience over principle.

However, expedience does not pay dividends. Alexander Hamilton, in defending the veto power in the federal Constitution, noted that the “stern virtue” to maintain principles over expedience “is the growth of few soils.” Fortunately, Gov. Mark Sanford is rooted in just such soil, and he did veto the unconstitutional, bobtailed bill last year. Subsequently, the other check (judicial review) came into play after the Legislature overrode the governor’s veto. At oral argument, S.C. Chief Justice Jean Toal labeled the Life Sciences Bill the “granddaddy of all bobtailed bills.”

There is a third check on legislative overreaching such as bobtailing, which is internal to the Senate — the lieutenant governor. He presides over the Senate. Lt. Gov. Andre Bauer could have declared the diverse bobtailed, last-minute amendments “out of order” for being in violation of the constitutional requirement of a single subject, and almost certainly prevented their attachment to the Life Sciences Act. Maybe this session he will be more active in protecting the governor’s veto power from unconstitutional erosion by the “impetuous vortex.” (Certainly, he would be more inclined to do so if the lieutenant governor were elected on a ticket with the governor, as is proposed in the governor’s restructuring initiative and supported by the MAP Commission.)

In any event, the Senate’s actions last week are a significant step forward. But all of us, whether we are citizens, the governor, the lieutenant governor, the courts or other legislators, must remain wary of those who have already “done found ways to get around this.”

Mr. Munson, a Greenville attorney, worked on Mark Sanford’s campaign and served on his transition team. He filed a brief with the Supreme Court in support of declaring the Life Sciences Bill unconstitutional.