Calling for new American leadership that is not "stuck in the 20th century," Republican Senator Marco Rubio officially launched his presidential bid Monday, a day after top Democrat Hillary Clinton announced her campaign.

Rubio, a 43-year-old Florida lawmaker and son of immigrants from Cuba who often casts his personal arc as the embodiment of the American Dream, presented the 2016 presidential election as "a generational choice about what kind of country we will be."

The remark, in a hometown speech at Miami's Freedom Tower that once processed Cuban immigrants into the United States, was a clear jab at his older rivals, notably Clinton, 67, and his fellow Republican and former mentor Jeb Bush, 62.
"While our people and economy are pushing the boundaries of the 21st century, too many of our leaders and their ideas are stuck in the 20th century," Rubio said to loud cheers.

"Now, the time has come for our generation to lead the way forward toward a new American century."

Rubio has enjoyed a remarkable political rise since running for Senate as an underdog in 2010, when he was swept into Congress on a conservative Tea Party wave.

Should he win in 2016 he would make history as the nation's first Hispanic commander-in-chief.

Equally at ease discussing foreign policy, deficit reduction, his family's compelling narrative or hip-hop music, Rubio took a direct swipe at Clinton.

"Just yesterday, a leader from yesterday began a campaign for president by promising to take us back to yesterday," he said as supporters booed at the mention of Clinton.
"But yesterday is over, and we are never going back."

Rubio joins two other Republican first-term senators who are already running: Ted Cruz of Texas, who is also Cuban-American, and Libertarian-leaning Rand Paul from Kentucky.

Cruz in a statement welcomed his friend to the presidential rodeo, saying Rubio will help "elevate the debate for all of us."

While Clinton has few serious Democratic challengers -- Vice President Joe Biden and former Maryland governor Martin O'Malley have expressed interest but little else -- several more Republicans may jump into the fray, including Wisconsin Governor Scott Walker and former Texas governor Rick Perry.

Should Bush, a former governor and the son and brother of two presidents, enter the race as expected, his duel against fellow Floridian Rubio could be a compelling narrative of the Republican primary.

- Shrinking the generation gap -
Rubio wants to take voters beyond the dynastic Bush-Clinton dynamic that has ruled national politics for much of the last three decades.

Youthful, charismatic and articulate on several issues, Rubio hopes to transcend the Republican Party's reputation for difficulty in connecting with young, Hispanic or African-American voters.

Rubio, a fierce critic of President Barack Obama's gentler approach on global issues, is hawkish on foreign policy, a Tea Party favorite with potential to draw conservative votes.

But he angered core conservatives two years ago when he helped craft a bipartisan immigration bill that would have provided pathways to citizenship for millions of undocumented workers, a plan he backed away from after it died in the House of Representatives.

Rubio's kickoff notably came just days after Obama shook hands with Cuban strongman Raul Castro at a regional summit, the visual symbol of a detente to which Rubio is fiercely opposed.

- Hillary hits the road -

Former secretary of state Clinton finally announced Sunday what everyone already knew: her intention to join the race to succeed Obama and give Democrats a third-straight presidential term for the first time in more than half a century.

Clinton immediately hit the campaign trail, striking a note of humility with her pledge to champion "everyday Americans" -- a departure from her hard-as-nails approach in 2008, when she lost her party's nomination to Obama.

Crowding into a van, she drove from New York toward the key Midwestern state of Iowa, where she will hold small roundtables with middle-class voters beginning Tuesday.

In her first fundraising email as a candidate, Clinton told supporters Monday she would "work my heart out" to earn votes.

"I've spent my entire life standing up for women, children, families, and anyone who needed a little help along the way," she wrote.

"That's what this campaign will be about, and that's what I'll do every single day as your president."

Clinton's first major rally and the speech that kicks off her campaign is not expected until May.

While Clinton aims to break the "glass ceiling" and become the nation's first female commander-in-chief, her Republican rivals want to reverse course from what will be eight years of Obama policies they say have made America weaker and economically stagnant.