Dozen Republicans now on US campaign trail, more likely

US real estate titan Donald Trump made his presidential campaign official Tuesday, becoming the 12th Republican to officially jump into the increasingly crowded 2016 pool.

Hillary Clinton leads a far smaller field of Democrats.

With four additional GOP candidates still seen as likely to enter the race, no fewer than 16 Republicans have emerged in the most wide-open nomination contest in decades.

– The declared –

– Jeb Bush: Florida’s ex-governor, who announced his bid Monday after months as a de facto candidate, is son and brother to two former presidents. The 62-year-old is the Republican most open to immigration reform. His network has raised vast sums of money, but he has been unable to break away from the pack.

– Marco Rubio: The 44-year-old US senator from Florida, elected in 2010, is the son of Cuban immigrants and, like Bush, speaks fluent Spanish. He advocates muscular foreign policy and US military re-engagement in the world.

– Ted Cruz: The senator from Texas, also 44, is an excellent orator, former lawyer, and flagbearer of arch-conservative causes.

– Rand Paul: A first-term senator like Rubio and Cruz, the 52-year-old Kentuckian represents the party’s libertarian wing, opposing mass NSA data collection and skeptical of military interventions abroad. His strategy includes drawing support from young people, African-Americans and Hispanics.

– Lindsey Graham: The 59-year-old foreign policy hawk is the fourth Senate Republican to run. He has backing from the likes of former nominee John McCain, but lags behind in polls.

– Ben Carson: A retired neurosurgeon who has never held public office, the conservative Tea Party favorite, 63, is the only African-American in the race.

– Mike Huckabee: The former Arkansas governor, preacher and television host makes his second presidential run. Huckabee, 59, hopes to capitalize on his rural evangelical following.

– Carly Fiorina: Hewlett-Packard’s ex-CEO spent millions from her personal fortune in an unsuccessful 2010 Senate bid. Fiorina, 60, is the only Republican woman running.

– Rick Santorum: The 57-year-old former senator from swing-state Pennsylvania and champion of the religious right and blue-collar Americans, won the Iowa caucuses in 2012 but ultimately lost the nomination.

– George Pataki: The three-term governor guided New York through the 9/11 attacks in 2001. Pataki, who turns 70 next week, calls himself a moderate who can overcome “partisan division.”

– Rick Perry: The three-term former governor of Texas, 65, botched his 2012 presidential bid. This time he cites his lengthy governing experience and lashes younger rivals for lacking it.

– Donald Trump: “The Donald,” 69, is America’s opinionated tycoon and brusque TV personality. On Tuesday he threatened to bring his business savvy into play if president, huffing: “I beat China all the time.”

– The all-but-declared –

– Scott Walker: Wisconsin’s fresh-faced governor, 47, earned national fame busting public unions, and claims as other conservative accomplishments tax cuts and legalizing the concealed carrying of firearms.

– Chris Christie: The blunt-talking New Jersey governor, 52, wants to reform the tax system, broaden national energy policy and “re-establish American leadership” worldwide.

– John Kasich: This fiscal conservative, 63, is governor of politically crucial Ohio. He has national security experience, having served on the House Armed Services Committee.

– Bobby Jindal: The Louisiana governor, 44, is son of Indian immigrants. Wonkish on policy, he has become chief advocate for repealing national educational standards.