His decision comes as former Rep. Karen Handel, who held the seat for a little over a year, considers a possible rematch. She defeated Democrat Jon Ossoff in a 2017 special election that attracted heaps of national attention, and was narrowly defeated by McBath in November.
Beach filed a statement of candidacy on Friday with the Federal Election Commission that allows him to immediately start raising money ahead of a March reporting deadline. He's allowed to collect cash during the legislative session because fundraising prohibitions apply to state, not federal, contests.
McBath's victory in the 6th District, which stretches from east Cobb to north DeKalb, was Georgia's most high-profile upset in the 2018 midterm. Many political handicappers saw Rep. Rob Woodall, a Republican who narrowly held a neighboring Gwinnett-based district, as far more vulnerable.
But the Democrat was helped by surging turnout in the state's marquee gubernatorial race, simmering suburban dissatisfaction with President Donald Trump and outside assistance from gun control groups who embraced McBath's message.
She has quickly become a leading national figure on the firearms debate. On the stump and in her television ads, McBath described how the death of her teenage son sparked her own activism, lobbying for stricter gun laws as a spokeswoman for the advocacy group Everytown for Gun Safety.
Republicans have criticized McBath's vote supporting Nancy Pelosi as the new House speaker, and any GOP opponent in 2020 is likely to also pounce on other votes they deem to be too liberal for the district, which was once represented by Newt Gingrich, Johnny Isakson and Tom Price.
But McBath will also seek to tie whoever she opposes to the more unpopular policies of Trump, including the Obamacare replacement plan he endorsed and the government shutdown that Democrats say is a crisis of his own making.
First elected to the Senate in 2013, Beach took conservative stances on some of the state's most heated debates, including votes to back the campus gun measure, restrict abortion and support a version of the "religious liberty" measure.
He's also carved out a reputation as one of the Legislature's leading voices on two other issues: He has pushed for the legalization of casino gambling to boost the HOPE scholarship and, as chair of the Senate Transportation Committee, sponsored a string of initiatives to expand mass transit.
Among them is a 2018 law that could pave the way for the region’s biggest expansion of mass transit in a generation by allowing 13 metro Atlanta counties to raise sales taxes to pay for new projects, if voters approve.
A touchstone of his campaign, Beach said, will be a demand that the federal government return to the states a portion of the gas tax in the form of block grants that Georgia can use for capital improvement projects.
He also said he would tout his votes on state legislation that appeal to a more moderate electorate, including votes on job training initiatives and tax cuts.
“Public education, transportation and job creation – that’s what I’m good at. That’s what I bring to the table,” he said. “I can win this. The Democrats worked for years to win this seat, and they did. I’m going to start early and win it back.”