Steve Russell speaks in August 2014 after winning the Republican primary runoff election for Oklahoma's 5th Congressional District in Oklahoma City. [Photo by Bryan Terry, The Oklahoman Archives]

When Oklahoma's 5th Congressional District — a three-county swath that includes Oklahoma City — last elected a Democrat, the year was 1974, the Republican president had just resigned and Democrats were gaining large majorities in both chambers of Congress.

Forty-four years later, the 5th District is trending Democratic again and Republicans nationwide are bracing for a potential wave election. Crystal Ball, a highly-regarded handicapper of political races, recently moved the 5th District from its “safe Republican” category to “likely Republican.” Whether a blue wave can reach Oklahoma is unclear but even the possibility has energized Democrats in the state's largest city.

“The takeaway here is that this is not a safe seat, and should be getting a lot more attention,” said Noah Rudnick, a political analyst whose statistical model was the basis for Crystal Ball's rating change.

Last week, Democrat Conner Lamb won a district in Pennsylvania that had voted overwhelmingly for President Donald Trump just 17 months before, the latest scare for Republicans in the 2018 election cycle. Trump won Oklahoma's 5th District by a smaller margin than he won Lamb's district in Pennsylvania.