President Trump’s potential meeting this week with his Russian counterpart could eclipse the diplomatic successes his team has notched in the early days of a five-country tour through Asia.

Secretary of State Rex Tillerson said Thursday that the rumored talks between Trump and Russian President Vladimir Putin on the sidelines of the Asia-Pacific Economic Cooperation summit in Vietnam remain under consideration. The Kremlin also indicated this week that the two counties are still discussing the prospect of a meeting at the trade summit in De Nang.

Trump himself said earlier this week that he believed he would sit down with the Russian leader during his 12-day trip.

“I think it's expected we’ll meet with Putin, yeah,” Trump said on Saturday. “We want Putin’s help on North Korea, and we’ll be meeting with a lot of different leaders.”

But the White House has not yet officially confirmed that the conversation between Trump and Putin will take place. And the prospective meeting — however focused on foreign policy it ends up being — could tear focus away from Trump’s tour of Asia and throw it back to the collusion scandal that has threatened to overshadow the president’s agenda at home.

“It's clear that Putin has been pursuing a strategy to disrupt the American political system, in part to bolster the relative importance of Russia in the world at a time when it faces a lot of internal problems,” said Grant Reeher, a political science professor at Syracuse University. “Just having the meeting could play into Putin’s hand in that disruption.”

The stated reason for Trump’s meeting with Putin — North Korea’s nuclear ambitions — has loomed large over much of Trump’s trip to Asia. During earlier stops in Japan, South Korea, and China, Trump has emphasized the need for all countries to cooperate in their efforts to cut Pyongyang off from the resources of the world and force North Korea’s unpredictable leader, Kim Jong Un, to the negotiating table.

Russia, however, has lagged behind other nations in severing its ties to North Korea amid Kim’s escalating series of missile and nuclear tests. While Trump has managed to pressure China into taking steps toward curbing its support of the Kim regime, any explicit efforts from Trump to pressure Putin into walking away from North Korea could expose the limits of his influence on the world stage and saddle him with the blame for a diplomatic failure if Moscow continues dealing with Pyongyang.

Jean Lee, a Korean expert at the Wilson Center, said North Korea has deployed a “divide and conquer” strategy that has recently tilted toward Russia.

“One of North Korea’s favorite tactics is to play ‘divide and conquer’ with its neighbors, and to grant one country access while punishing another with ignorance,” Lee said. “Right now, North Korean leader Kim Jong Un is playing that game with Russia and China by favoring Moscow while rebuffing Beijing."

Lee said North Korea would be left in a difficult position if Putin walked away from Kim at Trump’s behest, because Pyongyang “won't have any superpower favorites left to play off the others.”

“If Trump and Putin do sit down, it will be interesting to see how far Putin is willing to go in aligning with Washington on North Korea,” Lee said. “Russia has scaled back its economic assistance to North Korea drastically since the days when the Soviet safety net served as Pyongyang’s main lifeline. But Moscow does not want to completely give up its political leverage with Pyongyang.”

Trump’s North Korea strategy to date has focused heavily on convincing China to use its influence with the Kim regime to pressure it into abandoning its nuclear development.

China has shown some signs of cooperating. For example, earlier this year, Beijing rejected North Korean shipments of coal in an effort to show the Trump administration it was following through on pledges to cut Pyongyang off from the global economy.

But Trump has not gone after Putin with nearly as much aggression when it comes to North Korea. And changing that strategy could cause all future interactions between Moscow and Pyongyang to be viewed through the lens of Trump’s failure to sway Putin, a leader who has already caused him severe political headaches at home.

The FBI and a special counsel have spent months looking into whether Trump’s campaign teamed up with the Kremlin to manipulate public opinion during the 2016 race. Two former Trump associates have been indicted as a result of that investigation on charges unrelated to collusion, and one has pleaded guilty to making false statements to FBI agents about his contacts with Russia.

A meeting between Trump and Putin — even an informal one — could revive the Russia controversy that has so far laid dormant during Trump’s high-profile trip to Asia.

An informal meeting between Trump and Putin has caused problems once before.

When Trump traveled to Germany for the G-20 summit in July, he sat down with Putin for a highly anticipated bilateral meeting, during which he pressed the Russian leader about meddling in the U.S. election.

However, the White House took fire after a second, undisclosed conversation between Putin and Trump at a dinner for leaders and their spouses came to light. Although Trump’s aides described the meeting as a social interaction that came naturally in the course of a diplomatic reception, the meeting stoked concerns among Trump’s critics that the president sought to facilitate an inappropriately friendly relationship with the leader he has been accused of working with in secret.

Trump and Putin are both expected to attend the trade summit in Vietnam this week, and another informal conversation could easily occur even if the White House ultimately eschews a formal bilateral.

Reeher suggested a potential meeting between Trump and Putin could produce results under the right conditions.

“If President Trump and his advisers can out-think and out-strategize [Putin] in order to get Russia to provide some useful assistance in changing North Korea’s nuclear program, then it could be a win for the president, but it’s high-risk to say the least,” Reeher said. “Trump has far less leverage with him, and the meeting could bring renewed attention to one of his biggest political problems. Proceed with great caution.”