Barack Obama will become the first sitting president in 50 years to visit Puerto Rico when he arrives Tuesday in San Juan. But the trip also has a political component, including the message it sends to Latino voters on the mainland.

John F. Kennedy was the last president to visit Puerto Rico, making his stop while on the way to Venezuela and Colombia. Since then, Puerto Rico has been waiting — and waiting — for another president to drop in.

Obama did campaign in San Juan during the primaries in 2008. The welcome was less formal than a presidential visit, but the enthusiasm was obvious.

“We have great support here in Puerto Rico,” Obama said. And he promised that day to come back as president.

Obama will be on the ground In San Juan for barely five hours. There will be an airport welcome ceremony where he will make remarks. Then it’s off to the governor’s mansion for meetings with Gov. Luis Fortuno. Elected the same year as Obama, he’s a Republican who has more in common with the budget-cutting and tax-cutting Republicans in statehouses across the U.S. than with the president.

“What I aspire to do is make sure that we highlight the issues that affect the almost 4 million American citizens that reside here in Puerto Rico,” he told NPR in an interview Monday.

“Certainly, the economy is the No. 1 issue here — as well as in the rest of the country — and I’ll be raising that issue with the president and ways we can work together for job creation,” Fortuno said.

Also on the agenda: The ever-present issue of Puerto Rico’s status as a territory and the contstant talk of possible statehood. Obama has been neutral on that issue and no major announcements are expected as part of this trip. The president’s day also includes a fundraiser sponsored by the Democratic National Committee.

But perhaps the biggest impact of the trip will be on the mainland U.S.A., where Puerto Rican Americans now outnumber the total population living in Puerto Rico by about 1 million. They represent about 10 percent of all Latino voters in the U.S. — a group which voted overwhelmingly for Obama over John McCain in 2008.

The trip is aimed at a key element of President Obama’s base, said Felix Matos Rodriguez, a Latino studies scholar and the president of City University of New York’s Hostos Community College.

“He’s very aware that Puerto Ricans are an important component of the Latino population,” Rodriguez said. “There are large numbers of Puerto Ricans in some key states, and connecting with folks on the island sends a signal — not just to the people on the island but to the Puerto Ricans here in the mainland U.S. — that the president cares about their issues.”

And that’s the connection the president hopes to start making with his presence on the island Tuesday.

Copyright 2011 National Public Radio.