The 2018 election season begins in earnest Saturday, when candidates across the state begin officially filing for office.

Texas Gov. Greg Abbott will highlight the first day of action. He's scheduled to turn in his paperwork to election officials at an Austin American Legion, where he'll also unveil his "Front of the Line" plan for veterans.

Abbott's haste in filing his candidacy is understandable. The incumbent is not expected to receive a serious challenge in the March Republican primary. In fact, no Republican statewide official is expected to face a major challenge.

Much of the action will swirl around Texas legislative races, including several high-profile Senate contests in North Texas.

The retirements of several Republican members of the U.S. House has created rare openings in Texas' congressional delegation. And Rep. Pete Sessions has drawn several Democratic Party contenders for his Dallas-anchored House seat.

Here are some things to watch between now and when the filing period ends on Dec. 11.

Texas House

There could be at least 50 incumbent Republicans facing primary challenges in March. It's part of the ongoing struggle within the party between establishment Republicans and hard-right conservatives.