After Republican state senator
Frank Watson resigned, shortly after suffering a stroke, McCarter was appointed to fill his place in the
Illinois State Senate in February 2009. McCarter was described as "a reliable GOP vote in the state senate." On May 31, 2011, McCarter accused Democratic state Sen.
Mike Jacobs of punching him after a debate over an electricity rate increase, a claim Jacobs denied by saying in a televised interview that "the senator was full of shit" and "someone who couldn't even really polish my shoes". McCarter had noted that Jacobs' father was a registered lobbyist for the utility, but Jacobs' response was that "one thing he would not allow to happen would be for anyone to question my integrity." Jacobs also said this information had been fully disclosed, his constituents were aware of it, "and they would make a decision based on that". It was reported that McCarter filed a police statement over the incident. After the Senate
redistricting, parts of the old 51st, 54th, and 58th districts were combined to create the new 54th Senate District. Another incumbent Republican,
John O. Jones, was also drawn into the 54th district. However, Jones failed to adequately meet the petition filing requirements and did not appear on the ballot. After Jones ruled out an independent bid, McCarter ran successfully for the 54th district. He chose not to seek reelection in 2018. He was succeeded in the Illinois Senate by
Jason Plummer.
Committee assignments As of the 100th General Assembly, McCarter sits on the following committees: Appropriations II; *Environment and Conservation (Minority Spokesperson); Public Health; Local Government; Labor; and State Government. ==2016 campaign for U.S. Congress==