[3] In June 2003, Mayor Michael Bloomberg announced an executive order allowing city employees to report illegal immigrants to federal authorities.

[4] Monserrate, then chairing the Council's Black, Latino and Asian Caucus, argued that this order would worsen relations between immigrant communities and the police.

He responded by sponsoring a bill entitled "Access Without Fear", which would have forbidden city officials from revealing such information except as required by law.

[4] He joined director Stephen Frears in publicizing the immigration film Dirty Pretty Things to raise awareness of the issue.

[4] In late 2008, Monserrate opposed Mayor Bloomberg's planned use of eminent domain in the $4 billion Willets Point Redevelopment project in Queens.

Monserrate changed his mind and supported the development after being assured that one-third of the housing would be "affordable" and that the city would offer businesses an opportunity to relocate.

[14] Monserrate dismissed medical authorities' criticism of the Purification Rundown, saying, "This is the same type of thing they said about chiropractors twenty years ago.

[20][21] With the office of Lieutenant Governor vacant due to Eliot Spitzer's resignation, the tie could not be resolved, and the resulting legislative deadlock continued until July 9, when Espada rejoined the Democrats.

[23] A bipartisan nine-member committee recommended disciplinary action against Monserrate following his 2009 misdemeanor domestic violence assault conviction.

Despite having struggled to meet court-ordered financial obligations, Monserrate opened a campaign office and hired paid staffers.

[55] In February 2021, the New York City Council passed a local law by a 44-1 vote, barring former lawmakers from running for municipal office if they have been convicted of corruption.

The law was reportedly targeted at Monserrate,[56] who had announced his intent to again run against Moya and other candidates in the Democratic primary for his former seat on the New York City Council and was collecting campaign donations.

Monserrate filed a federal lawsuit, claiming that the law did not bar him from receiving matching donations and contending that keeping him off the ballot was unconstitutional.

[58] Monserrate was arrested on December 19, 2008 and accused of slashing Karla Giraldo, his girlfriend, in the face with a broken drinking glass during an argument in his Jackson Heights apartment.

[59] He was arraigned the same day and pleaded not guilty to the charges of second-degree assault, a felony that carried a maximum sentence of seven years in prison, and fourth-degree criminal possession of a weapon.

However, Giraldo later changed her account to match that of Monserrate, stated that the cuts on her face near her left eye from a broken glass resulted from an accident, and added that she was no longer cooperating with the investigation.

[71][72] In an appearance before the sentencing judge, William Erlbaum, on July 7, 2010, Monserrate again petitioned to have a court order prohibiting him from contact with Giraldo vacated.