What is a state government triplex?

A state government triplex is a term describing single-party control of three of a state’s highest executive offices: governor, attorney general, and secretary of state. Control of all three offices can help a party advance its governing agenda, while divided control can spark conflict within the executive branch.
Currently, there are 18 states with Republican triplexes, 17 states with Democratic triplexes, and 15 states where neither party has a triplex. In the 2018 elections, Democrats gained triplexes in Colorado, Illinois, Maine, New Mexico, and Wisconsin, while Republicans lost triplexes in Arizona, Kansas, Nevada, and North Dakota.
Republicans also gained the previously-Democratic triplex in Alaska while Democrats gained the previously-Republican triplex in Michigan.
The 15 states where neither party has a triplex include six where the governor’s party differs from the other two officials. The Democratic governors of Kansas, Louisiana, and Montana, as well as the Republican governors of Kentucky, Massachusetts, and Vermont, serve alongside an attorney general and secretary of state of the opposing party. With the exception of Kentucky, the governor’s party is in the minority in both chambers of the state legislature in each of those states.
Regularly-scheduled elections this year have the potential to change both Kentucky and Louisiana’s triplex status. All three executive offices are also on the ballot in Mississippi, where the governor and secretary of state are Republicans and the attorney general is a Democrat.