President Barack Obama‘s upcoming three-day visit to India aims to build on the momentum of Prime Minister Narendra Modi‘s week-long visit to the U.S. in September–a trip flush with soaring rhetoric and goodwill.

Both capitals are exuding optimism. Washington’s new ambassador to New Delhi, Richard Verma, proclaimed in an interview that President Obama’s visit would herald a “new era in India-U.S. partnership.” Headlines in Indian media suggest that the trip will galvanize the relationship.

Still, don’t expect the hoopla and hype to culminate in major substantive outcomes. Here are four reasons why:

1. It’s too soon. Mr. Obama and Mr. Modi met in Washington only four months ago. It’s difficult for both sides to put together a big-ticket agreement with so little lead time–especially when both leaders, despite pledges to deepen the relationship, have been consumed by many other foreign policy matters in recent months.

2. U.S. domestic politics. Many of India’s chief priorities are linked to protracted political debates in Washington that extend far beyond the bilateral relationship. For example, New Delhi wants Washington to address perceived restrictions on H-1B visas awarded to U.S.-based Indian workers–but this issue is tied to broader immigration reform, which is stymied in Congress. India wants to take advantage of U.S. liquid natural gas exports–but the United States has restrictions on sending such products to nations with which it has no free-trade agreement, and loosening the restrictions would require wider policy reforms.

3. The lingering influence of inconvenient Indian policies. The U.S. wish list is hindered by the resilience of dogmatic Indian policies. Many U.S businesses fervently want to invest in India’s services industry–but this sector, reflecting India’s traditional emphasis on state-centered economic policies, is deeply protectionist and hesitant to open up to foreign investment. Similarly, India’s legacy of nonalignment–a Cold War-era foreign policy strategy that eschewed alliances–means that Washington won’t easily get New Delhi to formally join the U.S.-led coalition against Islamic State.

4. Bilateral tensions. Despite major improvements in relations since the 1990s, U.S.-India ties remain plagued by policy divides on issues as diverse as how to deal with Russia and global climate-change negotiations. Mistrust lingers from the Cold War, and this ill will resurfaced in late 2013, when the arrest and strip-search of an Indian consular official living in New York plunged relations into deep crisis. Such baggage must be unpacked before milestone agreements and achievements can emerge.

None of this is to suggest that Mr. Obama’s visit will not yield deliverables. We can expect modest accords on defense, economics, and energy–-but nothing like the civil nuclear deal of 2008, which some described as the cornerstone of an emerging strategic partnership.

Today, that agreement remains largely unimplemented–-and stands as a symbol of unmet expectations. So let’s keep our expectations in check for Mr. Obama’s visit. It will feature much happy talk but few substantive outcomes.

The opinion expressed here is solely that of the author.

This article was originally published in The Wall Street Journal's Washington Wire.