Republican Tom Leppert, marking his last day as mayor of Dallas, on Friday will add his name to the long list of candidates running to replace retiring Sen. Kay Bailey Hutchison (R-Texas).

Dallas doesn’t allow elected officials to run for another position while they’re still in office, so Leppert told the city council on Wednesday that he would step down, and he told his Twitter followers on Friday that he would file paperwork to join the race.

“Making tough decisions in business and as Mayor was not easy, but I made the hard calls that are so lacking in Washington right now,” Leppert said on his new campaign website. “In the U.S. Senate I’ll help create jobs, be a watchdog for taxpayers, fight wasteful spending, reduce the debt and stop the President’s tax increases.”

Leppert is far from the first Republican in the race, however. Texas Railroad Commissioners Michael Williams and Elizabeth Ames Jones, former Solicitor General Ted Cruz and former Secretary of State Roger Williams are already in.

Lt. Gov. David Dewhurst is also considering the race. A mid-January Public Policy Polling survey showed he would be Republican primary voters’ top choice, but at that early date not all the candidates were included.

Hutchison was the first Senator to announce she would not run for re-election in 2012. After losing a gubernatorial primary in 2010, she was weakened and had already begun to attract primary opponents for the 2012 race.

Nonetheless, a Republican is expected to retain the seat, and Roll Call Politics rates the race Safe Republican.