Isaac Newton Skelton IV was an American politician and lawyer who served as the U.S. representative for Missouri's 4th congressional district from 1977 to 2011. During his tenure, he served as the chairman of the House Armed Services Committee. He was a member of the Democratic Party. On November 2, 2010, he unexpectedly lost his seat to Republican Vicky Hartzler amid a Republican landslide. Notably, he was one of three Democratic committee chairmen to lose reelection in the 2010 midterm cycle, alongside House Budget Committee chairman John Spratt of South Carolina and House Transportation and Infrastructure Committee chairman Jim Oberstar of Minnesota. He was the longest serving incumbent representative to lose re-election that cycle.

Missouri's 4th congressional district comprises west-central Missouri. It stretches from the northern half of Columbia to the southern and eastern suburbs of Kansas City, including a sliver of Kansas City in Cass County and parts of Blue Springs in Jackson County. It also includes the northern portion of Columbia, home to the University of Missouri.