Duckworth, who earlier this month became the first U.S. senator to give birth while in office, brought baby Maile with her to vote on the Senate floor, just a day after rules were changed to allow Duckworth and other senators to bring children younger than 1 with them to vote. Duckworth suggested the policy, arguing that Senate attendance requirements would be at odds with the difficulties of caring for a newborn.

🚨🚨 SENATE BABY ALERT 🚨🚨 pic.twitter.com/3VeYjudp8L

— Ryan Struyk (@ryanstruyk) April 19, 2018

Ahead of the historic appearance, Duckworth tweeted a photo of the outfit she’d laid out for her daughter, poking fun at a separate controversy over the Senate dress code.

I may have to vote today, so Maile’s outfit is prepped. I made sure she has a jacket so she doesn’t violate the Senate floor dress code (which requires blazers). I’m not sure what the policy is on duckling onesies, but I think we’re ready pic.twitter.com/SsNHEuSVnY

— Tammy Duckworth (@SenDuckworth) April 19, 2018

Duckworth made her return to the U.S. Capitol just nine days after giving birth. She voted against President Donald Trump’s nominee for NASA administrator, Jim Bridenstine. Despite her vote, Bridenstine was confirmed by a vote of 50 to 47.