Sen. Claire McCaskillClaire Conner McCaskillKoch-backed group launches six-figure ad buy against Heitkamp GOP Senate candidate slams McCaskill over Clinton ties Dems meddle against Illinois governor ahead of GOP primary MORE (D-Mo.) pushed back on recent questions about whether former Secretary of State Hillary ClintonHillary Diane Rodham ClintonKoch-backed group launches six-figure ad buy against Heitkamp Trump keeps up 'low IQ' attack on Maxine Waters GOP leaders to Trump: Leave Mueller alone MORE’s health should keep her from running in the 2016 presidential election.

“She knows how to ignore all the cheap shots and stay focused on the American people,” McCaskill said of Clinton during an appearance on NBC’s “Meet the Press” on Sunday.

Last week, Republican strategist Karl Rove questioned whether Clinton’s 2012 head injury should play a role in her decision to run for president.

McCaskill called Rove’s questions a “cheap political shot.”

“I think Karl Rove is struggling to be relevant” and “trying to be part of the conversation,” she said.

When asked about her support for President Obama during the 2008 Democratic primary, McCaskill said she had to make a “very tough choice” between “two amazing candidates."

Since that election, Clinton has served as secretary of State, which has “enhanced her resume,” McCaskill said.

“It’s her time, and I’m excited to try to be a part of it.”