A new poll from End Citizens United found the race for California’s 45th District essentially tied, as Democrats try to unseat two-term Republican Rep. Mimi Walters in their effort to win back the House.

Forty-eight percent of respondents backed Democratic challenger Katie Porter while 47 percent supported Walters in the survey conducted by GBA Strategies and shared first with Roll Call.

Walters is one of seven California Republicans running for re-election in districts that backed Hillary Clinton in 2016. She carried the Orange County-based 45th District by 5 points. Democrats believe the historically Republican stronghold is a midterm battleground this year.

Inside Elections with Nathan L. Gonzales rates the race a Toss-up.

Porter, a law professor at University of California, Irvine, has the endorsement of End Citizens United, which backs candidates who favor a campaign finance overhaul.