As Congress and many state legislatures get under way for the year, there are lots of new lawmakers out there starting to learn the ropes. It’s an exhilarating, exhausting time, and they’ll have plenty of questions about the challenges. But here’s one thing they might not even have imagined: The hardest part of their new jobs may be the most basic – casting a vote on legislation.

It seems odd, doesn’t it? And it actually took me a couple of decades in Congress before I realized it. I’d never reflected on the question until a constituent asked point-blank what I found most difficult about the role. I thought about the long hours, the time away from home, the criticism and pressure from pretty much every side (yes, even back then). Then I realized that it wasn’t the frustrations of the job that made it difficult, but its very core: deciding how to vote.

Lee Hamilton is a Senior Advisor for the Indiana University Center on Representative Government; a Distinguished Scholar at the IU Hamilton Lugar School of Global and International Studies; and a Professor of Practice at the IU O’Neill School of Public and Environmental Affairs. He was a member of the U.S. House of Representatives for 34 years.