Xi Jinping could hardly have scripted a more favorable moment. This weekend, the leaders of India and Russia will join him at a security summit in China — one leader pushed away by President Trump’s tariffs, the other brought out of isolation by his embrace.

For Prime Minister Narendra Modi of India, U.S. tariffs on Indian goods have raised doubts about leaning too heavily on Washington. For President Vladimir V. Putin of Russia, his red-carpet treatment in Alaska by Mr. Trump blunted Western efforts to punish him for the invasion of Ukraine.

At the center is Mr. Xi, turning America’s alienation of India into an opportunity, and finding validation for his own long alignment with Mr. Putin.

The summit of more than 20 leaders, mostly from Central Asia, followed by a military parade in Beijing showcasing China’s newest missiles and warplanes, is not just pageantry. It shows how Mr. Xi is trying to turn history, diplomacy and military might into tools for reshaping a global order that has been dominated by the United States.

“The success of Xi’s foreign policy strategy is reflected in the parade of leaders traveling to China,” said Jonathan Czin, a fellow at the Brookings Institution who previously worked at the C.I.A. analyzing Chinese politics. “Indeed, Xi today probably feels more besieged by visiting heads of state than encircled by the United States and its allies and partners.”

Mr. Xi, Mr. Putin and Mr. Modi will be attending the summit of the Shanghai Cooperation Organization, a Eurasian security group led by China and Russia, in the eastern city of Tianjin on Sunday and Monday.