The answer, delivered during a debate with Democratic challenger Adam Hamilton, aligned Marshall with President Donald Trump's freshly antagonistic posture toward Ukraine, which has spent more than four years defending itself against an invasion.

The Republican incumbent, Roger Marshall, is facing a surprisingly tough challenge from the Democratic nominee, Adam Hamilton.

© Pool photo by Charlie Riedel

At a rally in Kansas on Monday, President Trump looked to boost Republican Sen. Roger Marshall in his reelection bid. Marshall faces a surprisingly close race with his Democratic challenger, Pastor Adam Hamilton. William Brangham discusses the Senate race with Jared Cerullo of PBS Kansas, the host of the weekly current affairs show, "Kansas Week."