One of the most heated political races across New York City this summer is in Congressional District 11, the only one in New York City represented by a Republican. Rep. Dan Donovan faces a primary challenge from his predecessor, former Rep. Michael Grimm, for the seat, which covers all of Staten Island and part of Brooklyn.

The race has been a nasty one from the start, filled with both attacks on policy positions and personal attacks. Here are a few things to know about the candidates and the race:

Grimm resigned from his seat after pleading guilty to tax fraud

Grimm served in Congress for four years. He resigned in January 2015 after pleading guilty to one count of tax fraud.

Grimm admitted to cheating the government out of taxes and paying his workers under the table. He had been hit with a 20-count indictment earlier in 2014 that was related to an Upper East Side restaurant he owned prior to becoming a politician.

There was also a separate investigation into fundraising for Grimm's 2010 campaign. Grimm threatened NY1 reporter Michael Scotto on camera after being asked a question about that investigation following the 2014 State of the Union. He later apologized. (Grimm was never charged in connection with that investigation.)

While under federal indictment, Grimm defeated Domenic Recchia in an election to keep his seat. Ultimately, he announced his resignation before the year was over.

Grimm spent seven months behind bars. He made a $150,000 restitution payment by June 2017. Months later, he declared that he would run against Donovan.

Donovan served as Staten Island DA before winning a special election

Donovan declared his candidacy for Congress four days after Grimm resigned. He defeated Democrat Vincent Gentile in a special election in May, earning 60 percent of the vote. He was then re-elected with 57 percent of the vote.

Donovan was the Staten Island district attorney from 2003 until he was elected to Congress. The highest-profile case he oversaw during that time was the death of Eric Garner.

Donovan ran for New York State attorney general in 2010, but he lost to Eric Schneiderman in the general election.

The race has been ugly

Neither Grimm nor Donovan has been shy about attacking the other.

In late March, Donovan was accused of using his influence to help his girlfriend's son avoid spending a night in jail after he was arrested and charged with possession of heroin. Donovan dismissed the accusation  as "dirty politics."

On April 13, Donovan accused Grimm of engaging in dirty tricks at the Board of Elections. (The issue has been referred to prosecutors.) On April 24, the Grimm campaign said it would file cease-and-desist letters to radio stations that played Donovan's first campaign ad. A Grimm staffer filed a complaint with the Office of Congressional Ethics against Donovan's top staffer.

The pair has fought over who has done more to help Hurricane Sandy victims. Taxes have also become an issue.

Donald Trump looms over this race, too

Each candidate's support – or accused lack of support – for President Donald Trump has become an issue in the primary.

Both candidates competed for the endorsement of a president who won 56 percent of the vote on Staten Island in the 2016 presidential election.

Ultimately, that endorsement went to Donovan, announced in two tweets from the president.

Grimm has accused Donovan of not backing up the president enough. Donovan, in turn, has accused Grimm of "trying to cloak himself around the president."

Donovan has voted in line with Trump's positions about 85 percent of the time, according to FiveThirtyEight.com.

But his splits with Trump's positions have been high-profile ones. He voted against the American Health Care Act and the GOP's tax overhaul. He voted against a House bill that would penalize "sanctuary cities" for protecting undocumented immigrants, though he recently appeared to reverse course.

Grimm has been highly complimentary of the president since entering the race.

Both candidates have also sought the support of former Trump surrogates. Donovan has the support of former Mayor Rudy Giuliani, who is currently an attorney for the president. Grimm met with Steve Bannon in Washington last October but later denounced Bannon, and Anthony Scaramucci also headlined a Grimm fundraiser in May.

The winner will face a Democratic challenger

The June 26 primary will be followed by a general election against a Democratic candidate in November.

There are a total of six Democratic candidates in the race. Max Rose, Zach Emig, Radhakrishna Mohan, Paul Sperling, Omar Vaid and Michael DeVito met for a debate at Wagner College in late April.

The last Democrat to represent Staten Island was Michael McMahon. He served for one term in 2008 and was defeated by Grimm in 2010. (Coincidentally, McMahon was Donovan's replacement as the Staten Island DA, winning an election in November 2015.)

McMahon was elected to that seat after the incumbent, Republican Vito Fossella, declined to run for re-election following a series of controversies. Fossella had served five terms.