In Texas, voters will cast ballots in runoff elections between the top two candidates that advanced from the first round of voting back in March.
Marquee races to watch tonight include a Democratic U.S. House primary in suburban Houston marred by national party meddling, an historic Georgia governors race (where the nominee will be a woman for the first time in the state's history), and an expensive battle in a deep red Kentucky House district between two compelling Democratic candidates trying to wrestle a seat away from an incumbent Republican.
Polls close in Georgia and Kentucky at 7 pm EST, in Texas at 8 pm EST and in Arkansas at 8:30 pm EST.
2:15 p.m. - Democrats hope to flip the script in Kentucky's state capital
Kentucky's 6th Congressional District, which represents Lexington and the state's capital of Frankfort, is currently represented by Republican Congressman Andy Barr. Today, Democrats are hoping the candidate who emerges from the primary can capitalize on a political environment that re-elected Barr and voted for Donald Trump by 22 and 15 percentage points, respectively, in 2016.
Lexington Mayor Jim Gray and former U.S. Marine fighter pilot Amy McGrath present Democrats with two strong candidates that could potentially unseat Barr.
Gray and McGrath, who are also running against state Sen. Reggie Thomas and three other Democrats in Tuesday's primary, have both proven to be prolific fundraisers with uniquely compelling backgrounds who could give Barr the toughest race of his political career.
ABC News' John Verhovek reports.
1:30 p.m. - On campaign strategy: Democratic candidate for governor Stacey Abrams leaned hard to the left to motivate progressives
ABC News reported on Monday that Stacey Abrams reached out to Senator Bernie Sanders for an endorsement and spoke to him directly on the phone. During the course of their call, the progressive Vermont Independent decided to lend his support and get involved in the race.
Seeking the senator’s endorsement was an interesting and perhaps risky move for Abrams, an African American woman and Democrat running for governor in Georgia. Republicans have held the state’s governor’s office since 2003.
Instead of zeroing in on swing voters or moderate independents in the southern state, Abrams instead has run, unabashedly, as a liberal during the primary race and made the argument that bold policies proposals and grassroots energy might bring out enough Democrats in the state to flip the seat.
ABC News' deputy political director MaryAlice Parks and ABC News' Cheyenne Haslett report.
11:40 a.m. - A mother who lost her son to gunfire is running for U.S. Congress in Georgia: "To not do anything is a tragedy"
“I was just as angry and devastated on Friday with Santa Fe as I was for Parkland, because Jordan was the same age as all these children that have been gunned down,” Democratic candidate for Georgia's 6th Congressional District Lucy McBath told ABC News. Her son Jordan was 17 years old when he was shot and killed in 2012 by a stranger at a gas station.
Now, she's part of a growing movement: parents who are running for office because they've lost children to gun violence. Among this group is two parents from Parkland, Florida, who decided to run for their county's school board after their teenage daughters were killed in February.
“I never expected this to happen but I know that in light of all my experiences, to not to do anything is a tragedy in itself,” McBath said.
She'll face three other Democratic candidates on Tuesday: former TV news anchor Bobby Kaple, businessman Kevin Abel and management consultant Steve Knight Griffin. Kaple, who had $290,000 in the bank at the end of the pre-primary reporting period, has the endorsement of Congressional Black Caucus Chairman Cedric Richmond of Louisiana, and numerous prominent Democrats in the state.
ABC News' Cheyenne Haslett reports.
11:30 a.m. - As they leave the polls, here’s what Georgia voters are telling ABC News.
Angelica Geter, a public health scientist at the Morehouse School of Medicine, voted for Democratic candidate for governor Stacey Abrams: “We think about what happened in Alabama. The people who ultimately led that victory was black women. Black and brown women, having that particular vote. She’ll be fine,” said Geter, who is also an African American woman. If elected, Abrams would be the first ever female African American governor.
“I went with new. I think we’ve had old government for too long,” said a 58-year old state employee who voted for Democratic candidate Stacey Evans. The voter, who declined to give her name for privacy, said she was “hoping that enough people vote out the current majority.”
ABC News' correspondent Steve Osunsami reports.
6:00 a.m. - The Note: Democratic primaries the first test of electability in the South
In ABC News' daily political email newsletter, political director Rick Klein wrote about a commonality in these four states and their primaries: "With four red states voting on Tuesday, Democrats’ main problem at the moment isn’t in finding viable contenders so much as it is what to do with too many of them."
And deputy political director MaryAlice Parks wrote about the difference a Democratic wave could make in Texas, where voter turnout is low: "Experts say Texas’s low turnout has been partially due to a perception that few races were actually competitive. This year though, for the first time in 25 years, a Democrat is running in each of the state’s 36 congressional districts. More than a dozen Democratic congressional primaries were so jammed packed they went to the run-offs today."