The thing is, ahead of past expected Senate vacancies, rather than looking for a loophole, Massachusetts state legislators have opted to simply change the appointment rules. Multiple times.
In 2004, the Democratic-controlled State House pushed through a bill that stripped then-Gov. Mitt Romney of his power to fill Sen. John Kerry’s seat, presumably with a fellow Republican, as the Democratic senator ran for president. The measure—to keep the seat vacant until a special election was held in 145 to 160 days—was ultimately passed with a veto-overriding two-thirds majority, despite the fact the Kerry ultimately lost to incumbent President George W. Bush.
But then in 2009, with Democrat Deval Patrick as governor, state legislators passed a bill at the behest of Sen. Ted Kennedy to give Patrick the power to choose a replacement for the terminally ill Democrat.
Would Massachusetts legislators change the rules a third time for Warren? According to state House and Senate leaders, there are no such plans.