President Donald Trump's political groups have spent more than one-quarter of a billion dollars to bolster Republicans in the final stretch of this year's midterm elections, an unprecedented amount for a sitting president that underscores the stakes on Nov. 3.

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."