[6] However, The Oregonian had revoked the endorsement the day after giving it due to newly released reports showing companies she owned had lied about expenses submitted to ODOT for repayment, and then was found destroying evidence when records were requested in court proceedings.

The rulings ended with $60,000 in court costs,[7] and an assessment stating that while the company had willfully destroyed evidence, the resources needed to successfully prosecute a criminal case would require more than could be justified as an appropriate use.

Thatcher was one of several cosponsors of legislation in 2009 to establish an Oregon's first transparency website; the measure passed the Senate unanimously and was signed into law by then-Governor Ted Kulongoski.

[11] Thatcher was a chief sponsor of legislation signed into law in 2011 that expanded Oregon's transparency web site to include economic development tax incentives,[12] and in 2013 was a sponsor of legislation that required the state transparency website to post additional materials, such as minutes or summaries of public meetings, additional state contracts, and information on tax expenditures under Oregon Low Income Community Jobs Initiatives.

Thatcher has falsely claimed that the Arizona audit showed evidence of fraud and has declined to state whether Joe Biden won the 2020 election.

[25] While participating in a Republican-led walkout in May 2023 Thatcher reached the 10 unexcused absence threshold set by measure 113, disqualifying her from running for reelection after her current term ends.