NEW YORK — New York City Mayor Bill de Blasio finally announced that he is backing Hillary Rodham Clinton for President, a much-discussed endorsement that had prompted some criticism from fellow Democrats for being so long in coming.

The delay, which coincided with a push to make himself a national figure on liberal issues, had long puzzled some political observers because the mayor has longstanding ties with the Clintons.

De Blasio announced his endorsement during a high-point for Clinton’s Presidential campaign. The former Secretary of State has consolidated her status as the clear favorite for the Democratic nomination following a string of political triumphs, including a strong debate performance and the announcement by Vice President Joe Biden that he would not challenge her for the nomination.

With just over three months to go before the first primary contests, the Republican race remains far more crowded and unpredictable, as establishment favorites such as Former Florida Gov. Jeb Bush and Florida Sen. Marco Rubio strive to emerge from the shadow of insurgent outsiders Donald Trump and retired surgeon Ben Carson.

De Blasio said Friday that Clinton was the candidate best suited to navigate Washington and actually enact liberal policies to combat income inequality.

“The candidate who I believe can fundamentally address income inequality effectively, the candidate who has the right vision and the right experience to get the job done is Hillary Clinton,” he said during an early morning appearance on MSNBC’s Morning Joe.

The Associated Press and other media outlets reported that de Blasio had, at last, decided to end the months of speculation surrounding his endorsement and would back Clinton.

De Blasio worked in the Department of Housing and Urban Development under President Bill Clinton and was then plucked from relative political obscurity to run Hillary Clinton’s successful 2000 Senate campaign.

He remained close to the couple, who appeared on stage with him at his January 2014 inauguration. President Clinton administered his oath of office.

But de Blasio appeared on Meet the Press the April morning of Hillary Clinton’s campaign announcement and said that unlike other New York politicians — including both Senators and Gov. Andrew Cuomo — he would not automatically be backing the former Secretary of State.

“I think she’s one of the most qualified people to ever run for this office and, by the way, thoroughly vetted,” de Blasio said then. “But we need to see the substance.”

He stuck to that script in the coming months even as criticism mounted within the party. He also stuck to it during the rise of Vermont Sen. Bernie Sanders, who shares many of de Blasio’s left-leaning views and has become Clinton’s chief rival for the Democratic nomination.

The mayor also moved toward making himself a national figure on liberal issues, particularly on the fight against income inequality.

But polls reflected that many New Yorkers felt that de Blasio was prioritizing the national over the municipal and many of his advisers in City Hall urged him to simply take the plunge and endorse Clinton.

On Oct. 30, he finally did, and he offered a spirited defense of his former boss.

“There’s a lot of spine there and a lot of steel there,” said de Blasio. “She has said what she believes in. This is a very sharp, progressive platform and she has the ability to follow through on it.”

(JONATHAN LEMIRE)