Congressman Jeff Van Drew outraged New Jersey Democrats and delighted Donald Trump last year when he switched parties and pledged his "undying support" to the Republican president.
He will face challenges from all sides on Tuesday, as Democrats pick a candidate to challenge him in the November 3 United States national election and Republicans choose whether to let Van Drew seek a second term serving the state or give the chance to a rival Republican.
That is just one of the choices facing voters in the mid-Atlantic state of New Jersey on Tuesday. They, and voters in Delaware, will also cast ballots in presidential primaries, although the outcome is not in doubt. Former Vice President Joe Biden is the presumptive Democratic nominee, and Trump has no significant national Republican opposition.
Both primaries had been postponed because of the coronavirus.
Results in competitive congressional primaries may not be known until later this month. As with other states that have encouraged voters to mail their ballots instead of voting in person because of the pandemic, delays are likely while officials receive, open and tabulate the votes.
Voters in other states, including New York, are still awaiting official results from primaries held last month.
In New Jersey's 2nd district, which includes Atlantic City, Van Drew, 67, won as a Democrat in 2018. But he left the party a year later after voting against impeaching Trump in the US House of Representatives. Democrats presently control the US House of Representatives by a 233-197 margin.
The lineup of Democrats aiming to replace him includes former school teacher Amy Kennedy, wife of former US Representative Patrick Kennedy and part of the storied political dynasty, who is going up against local political science professor Brigid Harrison.
The two have split the state's Democrats: Governor Phil Murphy endorsed Kennedy, while Senator Cory Booker backed Harrison. Three other candidates round out the ticket.
Amy Kennedy, the wife of former US Representative Patrick Kennedy, is seeking support from Democratic voters in New Jersey to face Representative Jeff Van Drew in November [File: Rick Wilking/Reuters]
All the candidates have seethed over Van Drew's switch. When announcing her candidacy, Kennedy said Trump and Van Drew are "symptoms of a bigger sickness infecting our country and our politics".
Even Van Drew's conservative Republican primary opponent, Bob Patterson, hits him for becoming a Republican, saying "Switcheroo Van Drew" is unreliable.
Nonpartisan analysts rank the district as leaning Republican. Positions in three other competitive New Jersey districts are up for contention.
In New Jersey's 3rd congressional district, former construction company executive David Richter, 56, and Kate Gibbs, a 34-year-old former county official, are battling to take on Representative Andy Kim, who flipped the district in 2018's "blue wave" midterm election that saw dozens of Democrats win and allowed them to take House control.
In New Jersey's 7th congressional district, three Republicans, including Thomas Kean Jr, whose father was governor of the state, are vying to take on Tom Malinowski, who won the seat in 2018. Like Kim, Malinowski has no Democratic primary opposition.
In the 5th district, which Democrat Josh Gottheimer flipped in 2016, a progressive Democrat and neuroscientist, Arati Kreibich, is challenging him in the primary. She was endorsed by Senator Bernie Sanders, the democratic socialist who ended his presidential bid in April.
Booker, who ran an unsuccessful campaign for the Democratic presidential nomination, faces a progressive challenger who ran Sanders' presidential campaign in New Jersey. Black community activist Lawrence Hamm, however, has a massive fundraising disadvantage versus Booker, who is also Black.