Chuck Grassley, oldest GOP senator at 88, is running for reelection

Republican Senator Chuck Grassley, the oldest Republican senator at 88, is running for reelection next year. Grassley announced his bid on Twitter Friday morning with a short video of him on an early morning run, something he's known for, in a not-so-subtle message that he's still up to the task. 

"It's 4 a.m. in Iowa so I'm running. I do that 6 days a week," the tweet with the video said. "Before I start the day I want you to know what Barbara and I have decided. I'm running for re-election—a lot more to do, for Iowa. We ask and will work for your support. Will you join us?"

Grassley's bid keeps that seat safe in Republican hands. Grassley has held the seat since 1981, and if he wins again, it will be his eighth term. He is the longest-serving senator in Iowa history. Grassley won his last election in 2016 by 25 points.