On June 2, 2009, Barnett announced that he was a candidate for the Republican nomination for the United States Congress from the first district of Kansas.
Barnett subsequently resigned his state Senate seat, and resumed his medical career at a Topeka, Kansas, clinic.
As 2006 progressed, other candidates for the Republican nomination emerged, however none of them were able to match Barnett in campaign spending or statewide name recognition.
[6] His closest competitor was author Ken Canfield, who received 26%, followed by former state House Speaker Robin Jennison, who polled 22%..
[10] Jim Barnett had been considered a moderate alternative to Kris Kobach in the Republican Party primary for the 2018 election.
[13] Barnett told the Shawnee Mission Post he considers has stated that he believes former Kansas governor Sam Brownback's tax experiment "failed miserably from a budget standopoint.
[16][17] In June 2017, Barnett expressed concern that Congress would not allow states that have not already expanded Medicaid to do so and anticipated that repeal of the Patient Protection and Affordable Care Act would jeopardize healthcare for 440,000 Kansans.