– Things seemed to be going great in 2008 when the United States and India signed a nuclear deal that was to bring tens of billions of dollars and thousands of jobs to the U.S.

It never happened.

India passed a liability law that halted nuclear business investments before they even started. Relations soured more as the U.S. named India's rival Pakistan as an ally. Documents released by leaker Edward Snowden showed the National Security Agency authorized spying on Indian officials.

"The relationship drifted," said Michael Kugelman, program associate for South and Southeast Asia at the Woodrow Wilson International Center for Scholars.

Now, with an opening to restore relations with new Prime Minister Narendra Modi, Obama arrives in India on Sunday, becoming the first American president to visit India twice during his presidency.

U.S. officials said Saturday that Obama will cut short his trip and visit Saudi Arabia to pay respects after the death of King Abdullah. The schedule change, announced shortly before Obama left Washington on Saturday, means the president will skip plans to see the Taj Mahal.

"I know many of you have heard talk about the promise of this relationship for many years," Secretary of State John Kerry said in India this month. "I've heard it myself. But the fact is that now it is really being implemented."

Obama, accompanied by the first lady, will be Modi's official guest Monday at Republic Day, a national holiday marking the adoption of the constitution in 1950 that is celebrated with a parade through the streets of New Delhi.

Behind closed doors, Obama and Modi are expected to discuss a new defense agreement, climate change, trade, Islamic terrorist groups, Afghanistan, and even Mars exploration.

Obama has attempted numerous times to pivot to Asia but has often been distracted by other hot spots, from the ongoing battles in Iraq and Syria to Ukraine.

But administration officials said Obama has remained convinced of the importance of good relations with India, the world's second-most populous country with more than 1.2 billion people, a growing economy and middle class and a recent interest in playing a larger role in Asia and across the globe. It not only is important for the U.S. on a variety of issues, it sits strategically next to Pakistan and China.

The White House's attitude toward India shifted after Modi was elected in a landslide in May 2014. He is enormously popular for trying to streamline the country's notoriously corrupt and cumbersome bureaucracy and reinvigorate a sluggish economy.

"He immediately is prepared to engage the United States in a bigger way than I think most of us had envisioned just days prior to the election," said Rick Rossow, the chair in U.S.-India Policy Studies at the Center for Strategic and International Studies.