NEW DELHI — -- With new bounce in his step amid rising poll numbers at home, President Obama is pivoting to his agenda abroad.

Obama and First Lady Michelle Obama depart Saturday for a three-day visit to India aimed at bolstering ties with a rising economic and military ally, and burnishing his legacy on foreign affairs.

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“He sees this as a potentially transitional, if not transformational, moment for the relationship, because we have a very strong and clear indication from India’s leadership that they want to elevate our bilateral cooperation and our global cooperation,” said deputy national security adviser Ben Rhodes.

The trip may end up being largely symbolic, perhaps not producing many major policy agreements. Still, experts say Obama will make history on several fronts:

1st American President to Visit India Twice

Six U.S. presidents have visited India since its independence in 1947. Barack Obama will become the only one to visit twice.

“It is extremely significant for the president to go back to India a second time, to do it only as an India trip, to be the guest for [the Indian holiday] Republic Day,” said Richard Rossow, an expert in U.S.-India relations at the Center for Strategic and International Studies.

Obama scheduled his State of the Union address to specifically accommodate this trip, his aides say. He could have had an easy excuse to pass on the invitation. The trip comes unusually soon after the two leaders held a summit in Washington four months ago.

“The symbolism of all this is tremendous,” Rossow said.

The Obamas previously visited India in November 2010, making Obama only the second president after Richard Nixon to visit India in his first term.

1st American as 'Chief Guest' of Republic Day

For the first time in India’s 65-year history, an American president has the high honor of being the nation’s chief guest for an elaborate pageant of military and cultural pride on Republic Day.

Russia’s Vladimir Putin has had the honor. So, too, has Nelson Mandela, plus the president of Iran, the queen of England, the Japanese prime minister -- and even high-level officials from neighboring rival Pakistan.

“Frankly, it took us by some surprise,” Rhodes said of the invitation to Obama from Prime Minister Narenda Modi.

“There’s great affinity between the U.S. and India. But there’s also a history that is complicated and that would have made it seem highly unlikely that a U.S. leader would be sitting with India’s leaders at a Republic Day ceremony as chief guest,” he said.

The president and first lady will spend several hours viewing the parade and participating in ceremonial events and receptions that mark the 1950 birth of the world’s largest democracy.

In Open Air: POTUS to Spend Hours Outdoors Amid Terror Threats

Wherever the American president goes, so does his super-sized security apparatus. But never before has it been brought to bear on another country’s biggest national holiday celebration, in a capital city that’s one of the most densely-populated in the world.

Obama and Modi will spend several hours outdoors on an open-air viewing platform watching the Republic Day parade as tens of thousands of Indians pour into the streets -- a potentially risky setting that the U.S. Secret Service generally prefers to avoid.

“There’s not been a similar event that he’s attended overseas,” Rhodes said. “So this is unique in that case.”

There will be a seven-layer ring of security along the Republic Day route, according to local media reports. Satellites and drones -- operated both by Indian and American security services -- are expected to fly overhead.

More than 15,000 closed-circuit TV cameras will monitor the crowd, while more than 100,000 Indian policy and paramilitary forces will be on the ground, according to India’s Mail Online.

India’s top military officials have warned of potential terror strikes by Pakistani militants against soft targets in and around New Delhi ahead of Obama’s visit, putting officials and security services on high alert.

From Blacklist to Best Friend: Modi and Obama

Perhaps never before has a world leader gone from being on a U.S. blacklist -- denied a visa and cut off from diplomatic outreach -- to being a top priority of an American president in such a short turn.

Just one year ago, Modi was still sidelined by the U.S. for his alleged 2002 role in one of the deadliest religious riots in modern Indian history. He was accused of condoning the killing of some 2,000 Muslims in the state where he was governor.

But all has been forgiven, at least from the U.S. diplomatic perspective. After a September summit with Obama in Washington, the leaders' relationship has blossomed in unexpectedly positive ways, according to diplomatic observers and administration officials.

“This is a seminal moment in the bilateral relationship,” said Phil Reiner, the administration’s top adviser for South Asia. “The extension of this invitation by the prime minister really continues to set a different tone for our reinvigorated partnership.”

Doubling Down on Defense Deals

President Obama will see an awful lot of Russian military hardware paraded before him on Republic Day. The Russians have been India’s top defense supplier for decades.

But that’s starting to change, and Obama hopes to accelerate U.S. defense deals.

Overhead on Monday, he may spot an American-made C130J Hercules transport plane or a C17 Globemaster during the ceremonial fly-over. Soon, the Indians could be adding a new batch of Chinook and Apache helicopters to their fleet.

A number of defense deals are waiting in the wings, including one to bring production of lightweight American-designed artillery to India. Some of the deals are expected to be sealed shortly after Obama leaves.

There’s also word that renewal of the 10-year defense framework between the two countries is in the works -- a key piece of Obama’s “pivot to Asia” program and plan to counterbalance the rise of China.