For months, it appeared that New York Mayor Bill de Blasio might not have much of a political future. Federal and local prosecutors were pursuing parallel criminal probes into his fundraising activities. In February, Mr. de Blasio himself was called in for four hours of questioning.
But in a dramatic announcement on Thursday, prosecutors said they would not pursue charges against Mr. de Blasio or his aides, saying the evidence did not warrant any further action.
"After careful deliberation, given the totality of the circumstances here and absent additional evidence, we do not intend to bring federal criminal charges against the mayor," said Joon Kim, the acting top federal prosecutor in Manhattan, in a statement.
The announcement is a major boost to Mr. de Blasio's re-election hopes. Mr. de Blasio, a Democrat, is seeking a second term at the city's helm in November. If his legal woes had intensified, he was expected to face a strong challenge from other Democrats in the mayoral primary. Now his path to another term in office will face few, if any, obstacles.
The move also came just days after Preet Bharara, the former top federal prosecutor in Manhattan, was fired by U.S. President Donald Trump as part of a broader purge of Obama-era officials. Mr. Bharara had made the pursuit of corruption by elected officials a significant focus of his tenure.
At a press conference on Thursday, Mr. de Blasio claimed vindication. His conduct and that of his team was "legal and appropriate and ethical throughout," he said. He noted the length of the investigation, which took more than a year. The probe absorbed "time and energy that could have been used to serve the people of New York," Mr. de Blasio said. "I was obviously pleased to see the issue closed."
The two probes were conducted by federal prosecutors and by Cyrus Vance, the Manhattan district attorney. Federal prosecutors focused their investigation on whether Mr. de Blasio facilitated special treatment for individuals who donated to his original election campaign in 2013 and to his non-profit group, the Campaign for One New York (the organization has since closed).
In his statement on Thursday, Mr. Kim said there were several instances where Mr. de Blasio and his associates "solicited donations from individuals who sought official favours from the city" after which the mayor made inquiries to relevant city agencies on behalf of those donors.
But the evidence at hand fell short of the threshold necessary to prove any criminal intent. Mr. Kim said prosecutors took the unusual step of commenting on the status of a investigation in order not "to unduly influence" the upcoming mayoral campaign.
Meanwhile, Mr. Vance's office probed an effort by Mr. de Blasio's inner circle to help elect Democrats at the state level in 2014. Close associates of Mr. de Blasio allegedly devised a scheme to circumvent campaign-contribution limits by individuals, funnelling money through party committees at the county level.
While prosecutors ultimately decided not to prosecute, the move should not be interpreted as "an endorsement of the conduct at issue," wrote Mr. Vance in a letter to the New York State Board of Elections on Thursday. "Indeed, the transactions appear contrary to the letter and the spirit" of campaign finance law.
Experts on New York politics said they couldn't think of a comparable situation in which the city's mayor had faced a probe – and had been questioned – by federal prosecutors. "The mayor, one day ahead of St. Patrick's Day, must have a four-leaf clover in his pocket," said George Arzt, a Democratic political consultant and former aide to New York mayor Ed Koch. "Having criminal issues put aside is a major, major victory for him."
One official said that Mr. de Blasio had learned a costly lesson about blurring the distinction between fundraising efforts and political favours. "This decision means the case won't be hanging over his head during his re-election campaign," said a senior Democratic official in New York, who spoke on condition of anonymity. "But he will need to focus a lot of attention on creating a stronger firewall than existed before so he doesn't run into the same problem."