Russia and China could become more aggressive over the next two years if they conclude that President Donald Trump is politically weakened and on "his way out" after Democrats won control of both chambers of Congress, Brookings Institution senior fellow Robert Kagan told CNBC.
Speaking on "Squawk Box Asia," Kagan said the war with Iran had also exposed how Washington has "proved itself rather incapable militarily" in terms of capacity, which would be critical in Asia.
"Everybody can see how much our stocks are depleted in terms of interceptors and missiles, which are of vital interest in the Asian theater," he said.
Congressional Budget Office reports have estimated that the conflict depleted as much as two-thirds of U.S. missile-defense interceptors since June 2025, largely because of efforts to defend Israel against Iranian attacks. This could leave the U.S. with constrained inventories for several years.
Kagan said the deployment of three U.S. aircraft carriers to the Middle East had reduced the U.S. naval presence available in Asia, potentially giving China more room to act assertively in the region.
"I think Trump's only interest right now is in cutting economic deals with China. I don't think he has any real interest in confronting China, but that is going to lead China to be even more aggressive," he said.
In December, Trump approved an $11 billion arms package for Taiwan, but later held back on a second package worth about $14 billion, calling it a "bargaining chip" in talks with China.
China claims self-governing Taiwan as its territory. While Washington does not have a mutual defense treaty with the island, U.S. law requires it to provide Taiwan with the means to defend itself.
Former CIA Director William Burns said in 2023 that Chinese President Xi Jinping had instructed the military to be ready to invade Taiwan by 2027, while stressing that this did not mean Xi had decided to launch an invasion that year or at all.
Kagan's comments come as U.S., China and Russia discuss a possible trilateral summit between Trump, Xi and President Vladimir Putin at the APEC Leaders' meeting in Shenzhen later this month.
Chinese Foreign Ministry spokesperson Mao Ning said Wednesday that Beijing was "in communication with relevant parties regarding a meeting between the three heads of state," although no agenda has been announced.
Putin had reportedly floated the idea of a three-way summit with Trump and Xi in October to discuss ending the war in Ukraine, without Ukrainian President Volodymyr Zelenskyy at the table.
"If it's clear that Donald Trump is on his way out, and the United States may be returning to something like normal, I don't want to overstate that, but they may feel both of them, both Russia and China, may feel that the time to move is in the next two years," Kagan said.