DOWNERS GROVE, Ill. — Rep. Peter Roskam has spent months preaching the benefits of Republicans' $1.5 trillion tax cut to voters in his suburban swing district just outside of Chicago.
Roskam, a chief architect of the sweeping new law, argues it has jump-started economic growth. He credits the tax cuts with replenishing Medicare's health insurance fund, galvanizing manufacturing in his district and spurring companies to hire more workers.
But there's one thing they may not be able to do: save his own job.
"This race is close because we're in a tumultuous season in our public life," Roskam said in an interview with CNBC.
The tax cuts were supposed to be the centerpiece of the Republican campaign in the midterm elections. Instead, the GOP's singular legislative achievement has been overshadowed by trade tensions, the fight over the Supreme Court and President Donald Trump's Twitter feed.
Now Roskam is on the front lines of the battle for control of Congress. The voters in his district are affluent, well-educated — and, along with moderates suburbs like this one across the country, starting to lean to the left.
A recent poll shows Roskam slipping behind his Democratic opponent, political newcomer Sean Casten. Outside liberal groups are funding a late-stage ad blitz, and Casten announced one of the largest fundraising hauls of any congressional race during the third quarter.
"No one would've thought that Peter Roskam would be in any trouble," said Kyle Kondik, managing editor of Sabato's Crystal Ball, a political newsletter published by the University of Virginia's Center for Politics. "But Trump taking over the Republican Party … has had negatives in some places, too, and this district is a prime example."