MIAMI — Sen. Marco Rubio on Monday kicked off his 2016 candidacy with calls to re-energize the U.S. at home and abroad through a new generation of leadership prepared to tackle daunting domestic and foreign policy challenges.

In an energetic, made-for-television stump speech from Miami's historic Freedom Tower, the Florida Republican took square aim at President Obama, and by extension, his presumed Democratic heir apparent, former Secretary of State Hillary Clinton.

"We can't do that by going back to the leaders and ideas of the past. We must change the decisions we are making by changing the people who are making them. That is why today, grounded by the lessons of our history, and inspired by the promise of our future, I announce my candidacy for President of the United States of America, Rubio said, before a packed room of approximately 1,000 cheering supporters and overflow crowd in an adjacent parking lot who watched on a jumbotron.

In urging Americans to embrace a 43-year-old first-term senator as their next president, Rubio also subtly, but unmistakably, took a swipe at his more seasoned Republican competition for the GOP nomination, particularly former two-term Florida Gov. Jeb Bush, 62, considered one of his early political mentors.

"In many countries, the highest office in the land is reserved for the rich and powerful. But I live in an exceptional country where even the son of a bartender and a maid can have the same dreams and the same future as those who come from power and privilege," Rubio said during a high-energy event with historical resonance for Magic City residents. (The Freedom Tower once processed Cuban exiles upon their arrival in America.)

Rubio, known for charismatic, emotionally-charged speeches, was a hit in the room. The address, in fact, was quintessential Rubio, soaring in its rhetoric and grounded in Rubio's personal story as the son of poor Cuban immigrants who disdained Fidel Castro's dictatorship and who saw the U.S. as a beacon of freedom that would provide their children with a better life. Rubio only appeared to go off scrip once, when he made reference to the authoritarian regimes in Cuba and Venezuela.

Shane Connolly, 35, a Rubio of supporter from Miami, said he choked up when the senator talked about his parents, poor immigrants from Cuba who worked as a bartender and a maid but hoped for a better life for their children. "His story — the story of the American dream; his father being a bartender in the back of the room to him being a podium in the front of the room. That spoke to me." Rubio often tells the story, as he did in his this speech, about his father going unnoticed behind a bar but working hard so that one day his son might become something more.

Rick Cook, 62, another Rubio backer from the Miami area, said he was drawn to Rubio's call for a new generation of leadership. "The new direction — we're getting the old and the old and the old. We need something new," he said.

Rubio becomes the third prominent Republican to declare for president, following Sens. Ted Cruz of Texas and Rand Paul of Kentucky. If he is nominated he will be the first Hispanic to lead a major party ticket, and he'll be the first Hispanic president if he wins. (Cruz would hold the same distinctions if he won.)

Rubio's White House launch, and his decision to forgo re-election to the Senate, have been anticipated for weeks. But the senator didn't make it official until Monday morning, when he informed key supporters of the move.

Cruz welcomed his fellow Cuban American into the contest, saying in a statement that "Marco is a talented communicator and part of a new generation of Republicans stepping forward to promote conservative solutions to our pressing challenges. He is a strong addition to the Republican field, and he will undoubtedly elevate the debate for all of us." Tea Party groups, which have opposed Rubio on immigration issues, also welcomed him into the race as a conservative champion.

The Democrats immediately panned Rubio's candidacy, warning Hispanic voters in a series of press releases in English and Spanish that the senator's policies would damage their well-being.

Hispanics delivered 73 percent of their vote to Obama in 2012, and the quick attacks — while standard operating procedure for the Democratic National Committee when any top Republican runs for president — could signal anxiety that Rubio threatens the party's monopoly on the Hispanic vote.

"As a presidential candidate, Rubio's poll numbers with Latinos are just as bad as the rest of the GOP field — if not worse — and after a look at his policies, it's easy to see why," the DNC declared, in a release titled "Five things Latinos Need to Know About Marco Rubio."

Rubio's campaign slogan is "Marco Rubio; A New American Century," in line with his pitch to re-assert the United States overseas as the globe's preeminent economic power as well as its indispensable — and only — superpower. The intention of Rubio's address Monday, and his campaign going forward, is to promote his hawkish foreign policy and free-market domestic policies as the way to make the 21st Century another "American Century," as the 20th Century was often described.

"At the turn of the 19th century, a generation of Americans harnessed the power of the Industrial Age and transformed this country into the leading economy in the world. And the 20th century became the American Century. Now, the time has come for our generation to lead the way toward a new American Century," Rubio said. "This election is not just about what laws we will pass. It is a generational choice about what kind of country we will be."

Immediately following the speech, Rubio joined conservative Fox News personality Sean Hannity for an hour-long interview. On Tuesday, Rubio was scheduled to be in Washington for briefings and Senate Foreign Relations Committee hearings surrounding the framework to limit Iran's nuclear weapons capabilities that the Obama administration and world powers are negotiating with Tehran. Rubio opposes the outline of the deal that has emerged.

Rubio will stay in Washington through Wednesday for a tax-related event, before heading to Boston and New York on Thursday for fundraisers. The senator is scheduled to be in New Hampshire, host of the second nominating contest of the GOP primary, on Friday. Visits to Iowa, South Carolina, and Nevada, are in the scheduling process. The senator acknowledged that a presidential campaign would in fact keep him on the road and away from his wife, Jeanette, and four young children.

"The next 19 months will take me far from home. I will miss watching Amanda run track, Daniella play volleyball, Anthony play football and Dominick play soccer," Rubio said. "But I have chosen this course because this election is about them. Theirs is the most important generation in American history."