Former Maryland governor Martin O’Malley said Sunday that the presidency “is not some crown to be passed between two families,” sounding more resolute than ever about taking on Hillary Rodham Clinton for the Democratic nomination.

O’Malley, who has been aggressively positioning himself as a more liberal and forward-looking alternative to Clinton, said during an appearance on ABC News’s “This Week” that “new perspective and new leadership is needed.”

“Let’s be honest here,” O’Malley told host George Stephanopoulos. “The presidency of the United States is not some crown to be passed between two families. It is an awesome and sacred trust to be earned and exercised on behalf of the American people.”

Although his comments were an obvious reference to the Bush and Clinton families, O’Malley demurred when Stephanopolous asked which two families he was referring to, saying it could be “any two families.”

The appearance comes as O’Malley has stepped up travel to early nominating states but faced questions about how directly he is willing to take on Clinton, who holds a commanding lead in early polls and whom O’Malley enthusiastically endorsed when she ran for president in 2008. Many Democrats have speculated that O’Malley is angling to be Clinton’s vice presidential candidate or a cabinet secretary. O'Malley has said he will decide whether to move forward with a White House bid this spring.

Asked by Stephanopolous about his earlier endorsement of Clinton, O’Malley said Clinton had been the most prepared candidate “for those times.”

“I think our country always benefits from new leadership and new perspective,” O’Malley said.

He pitched himself as an executive with 15 years of experience — eight as governor of Maryland and seven as mayor of Baltimore — who had accomplished a good deal in Maryland and is willing to stand up to Wall Street and other special interests.

Asked whether Clinton is not willing to stand up to special interests, O’Malley said: “I don’t know. I don’t know where she stands.  Will she represent a break with the failed policies of the past? I don't know.

Stephanopolous said he was surprised by the forcefulness of O’Malley’s answers. “I wasn’t expecting you to be this direct,” the host said.

O’Malley brushed off questions about the lack of enthusiasm for a White House bid among fellow Marylanders in an October poll published by The Washington Post.

That poll showed that Clinton was the choice for president among 63 percent of Maryland Democrats, while O’Malley drew the support of only 3 percent.

During Sunday’s interview, O’Malley also said that a nuclear-armed Iran would present the greatest “man-made” danger to American interests.

He was highly critical of the 47 Republican senators who recently signed an open letter to Iran’s leaders over negotiations on that country’s nuclear program.

“If you hate the president of the United States more than you distrust the ayatollah, then you probably shouldn’t be in the United States Senate,” O’Malley said.

He also asserted that Maryland had “passed some of the earliest and strongest sanctions against Iranian nuclear development of any state in the nation.”

Aides cited 2012 legislation that barred companies from doing business with the state of Maryland if they were invested in Iran and a 2008 measure that divested the state's retirement and pension system from companies that do business in Iran's energy sector.