One of the larger unknowns is whether Democratic state Rep. Brett Hulsey, of Madison, will get the 2,000 signatures needed to challenge former state Commerce secretary Mary Burke. Hulsey is mounting a longshot campaign to take on Burke, the expected nominee to take on Republican Gov. Scott Walker.
Candidates for all state legislative races, as well as attorney general, also must file by 5 p.m. Monday.
If two or more candidates are running for the same office, they will face each other in an Aug. 12 primary. The general election is Nov. 4.