Mark Waller defeated incumbent Rep. Douglas Bruce in the contested Republican primary in August, taking 52 percent of votes cast. Waller faced Democrat Leslie Maksimowicz in the November 2008 general election. Waller's candidacy was endorsed by the Denver Post and the Colorado Springs Independent, and he won election to the legislature with 66 percent of votes cast.
2009 legislative session
For the 2009 legislative session, Waller was named to seats on the HouseEducation Committee and the House Judiciary Committee. Waller sponsored legislation to require disclosure on clothes collection bins operated by for-profit companies, to include a new derivative of methamphetamine to Colorado's list of banned drugs, and to exclude dry-ice bombs from a felony list of explosives, and to allow homeschooled students to enroll in college classes.
2010 legislative session
During the 2010 legislative session, Waller concentrated on criminal-justice related bills. A bill based on Governor Bill Ritter's criminal justice commission addressed reforming possession-related drug offenses, reducing some of the felonies and redirecting money toward treatment and recidivism reduction. Waller also worked to stop House Bill 1205, a military exclusion bill that Waller viewed as unfair in regards to private property rights; he sought to reconcile interests of both military installations and private property owners, particularly in terms of the prevalence of both within his district.
2010 election
Waller defeated Democrat Marcus Cimino with 74.7% of the 26,229 votes cast in the 2010 Midterm Election.
2011 legislative session
2012 legislative session
2012 election
In the 2012 General Election, Representative Waller faced Libertarian challenger Larry Reedy. Waller was reelected by a margin of 73% to 15% with other third-party candidates garnering the remainder of the vote.
2013 legislative session
Waller served as House Minority leader during the 2013 legislative session. A bipartisan effort with Democrat Pete Lee passed legislation that moved forward the state's restorative justice programs, albeit with compromises acknowledged on Waller's part.
Following a defeat of his primary opponent Tim Geitner, Waller was sworn in as El Paso County Commissioner for District 2, which encompasses the eastern side of Colorado Springs and the eastern edges of El Paso County. Waller took his seat early due to his predecessor, Amy Lathen, exiting her position for another job in June of 2016. Waller's four year term began on January 11, 2017 following his win in the November 2016 General Election.
2020 election
Waller declared his candidacy for the position of District Attorney in the 4th Judicial District in June of 2019. He faced Senior Deputy District Attorney Michael Allen in the GOP primary, held June 30, 2020. Both Waller and Allen secured multiple endorsements early in the contest; Waller's included El Paso County SheriffBill Elder, while Allen was endorsed by John Suthers Allen won the race on June 30 by around 8,000 votes. Waller's term as county commissioner ended after 2020.