Seliger served four terms in the nonpartisan position as mayor of Amarillo. He is also a former city commissioner and a former member of the Amarillo Civil Service Commission. He also served on former Texas Attorney General John Cornyn's Municipal Advisory Committee and, in 2002, he was appointed to the Texas Alcoholic Beverage Commission by Governor Rick Perry. Seliger was sworn into the TexasSenate on March 2, 2004, to complete the term of Teel Bivins of Amarillo, who obtained a diplomatic appointment as United States Ambassador to Sweden from the administration of U.S. President George W. Bush. Seliger was reelected to serve a full, four-year term on November 4, 2004. The district spans twenty-six counties and serves large slices of the Panhandle and Permian Basin, including Amarillo, Midland, Odessa, and Big Spring. It is one of the most Republican districts in the state; he has only faced a Democratic opponent once, during his first bid for a full term in 2004. Seliger is a member of the American Legislative Exchange Council, serving as Texas state leader. Seliger was appointed by Lieutenant GovernorDavid Dewhurst to serve as Vice-Chair of the Criminal Justice Committee for the Seventy-ninth Texas Legislature. In addition, he was appointed to the Natural Resources, International Relations and Trade, and Administration Committees. Seliger filed and sponsored over seventy-five bills, fifty of which were passed in one form or another during the regular session of the 79th Legislature. As the vice chairman of the Senate Criminal Justice Committee, Senator Seliger passed House Bill 2577 requiring local law enforcement agencies to report to the state the reason for a peace officer's termination to protect the integrity of the state's law enforcement officers. This legislation prevents those peace officers with a history of poor performance or unethical behavior, termed "gypsy cops," from taking advantage of police departments that lack the resources to investigate their employment history. Seliger's membership on the Senate Natural Resources Committee aided him in passing several important bills for West Texas. House Bill 2161 ensures that effective pipeline safety standards are in place for all construction work around oil and gas pipelines. It also establishes a program to address abandoned or orphaned oil and gas wells and includes considerations for potential future periods of decline in oil and gas prices. Additionally, House Bill 951 will establish a notice and remediation process for construction around pipelines. The Texas Municipal League presented Seliger with its 2005 Distinguished Legislative Service Award for his dedication to protecting and promoting local control. He also received the 2005 Rural Legislator of the Year Award from the Association of Rural Communities in Texas. Seliger won re-nomination to a full four-year term in the state Senate in the Republican primary held on March 4, 2014. He defeated attorney and former Midland Mayor Michael Jackson "Mike" Canon, Sr., 36,623 to 33,223. Seliger is a moderate Republican by Texas standards. He is considered one of the most moderate of the twenty Texas Senate Republicans, along with Kevin Eltife of Tyler, according to an analysis by Mark P. Jones of the political science department at Rice University in Houston. Jones also found that these Republicans saw passage of 90 percent of the bills for which they voted. In February 2015, Seliger filed proposed legislation backed by many school districts that a graduation committee be appointed for each pupil who twice fails an end-of-course assessment. With a unanimous committee vote, the student would be allowed to graduate from high school. The committee would consist of a principal, counselor, teacher, and parent and would consider course grades, standardized test scores, and regularity of attendance as factors to permit graduation in such situations. A. Marcus Nelson, superintendent of the Laredo Independent School District endorsed Seliger's bill, which he said would impact 172 pupils in Laredo who have twice failed the end-of-course assessments. "We need to find the right balance in the number of assessments and the accountability that goes with it," Nelson said. Seliger is the recipient of the Bell Helicopter 2012 Legislative Leadership Award, the Texas Municipal League's 2011 Legislator of the Year, the Texas District and County Attorneys Association's 2009 Law and Order Award, Legislator of the Year 2009 from the Associated Security Services and Investigators of the State of Texas and the citizens of Odessa honored him with the 2009 Heritage of Odessa Foundation Community Statesman Award in Government. In the general election held on November 6, 2018, Seliger handily prevailed over his only opponent, the Libertarian Jack B. Westbrook, 171,831 votes to 24,458. No Democrat sought the seat. Seliger's status as a Moderate Republican wields him potentially great power in the state Senate. He can join with the body's twelve Democratic members to block conservative initiatives from coming to the floor. In 2019, Seliger announced opposition to the property tax relief package offered by Lieutenant GovernorDan Patrick, Governor Greg Abbott, and House Speaker Dennis Bonnen, who maintain that the issue of runaway property taxes has reached emergency status. Seliger, however, said that municipalities and counties should be able to set their own rates in conjunction with value estimates from the appraisal boards and the will of local voters. Under the measure, counties with more than $15 million in combined property and sales taxes must obtain voter approval for any increase in property taxes greater than 2.5 percent of the current year rates.
Removal from Agriculture Committee chairmanship
On January 22, 2019, Seliger was removed as chair of the Texas Senate Agriculture Committee after suggesting that a female staffer at the Capitol in Austin kiss his posterior. Seliger previously compaoned that he had been named the chair of the Agriculture Committee. A senior staffer for Lieutenant Governor Patrick, Sherry Sylvester, responded to Seliger's complaint by stating that if Seliger believed being chair of Agriculture was beneath him then he should step down and let Patrick appoint someone else to the job. On the radio show, "Other Side of Texas," Seliger said, "It was extremely snide and really unbecoming for a member of the staff, the lieutenant governor’s or my staff. I didn’t say anything of the sort, and that assertion is disingenuous and I have a recommendation for Miss Sylvester and her lips and my back end." Patrick then removed Seliger from the chairmanship after Seliger was given forty-eight hours by Patrick to apologize to the female staffer. Seliger refused to make the apology. Patrick then awarded the chairmanship of the Agriculture committee to state Senator Bob Hall.
