At a rally Tuesday in Allentown, Pennsylvania, President Donald Trump said North Korean leader Kim Jong Un, Russian President Vladimir Putin and Chinese leader Xi Jinping prefer him to win the November election over Democratic nominee Joe Biden.

Trump characterized these foreign leaders as “sharp as a tack” and said, “they don’t want to deal with sleepy Joe.”

Former President Barack Obama shot back at Trump’s foreign leader remarks Wednesday in a speech in Orlando, Florida. “That’s not a good thing. You shouldn’t brag about the fact that some of our greatest adversaries think they’d be better off with you in office,” Obama said.

The U.S. has a long history of tense relations with Russia, China and North Korea.

"The United States’ relationship with Russia is today the worst that it has been since 1985," according to a report in April by the Brookings Institute.

The U.S. and China have a complicated relationship for decades that has grown more strained due to the recent trade war.

Trump has often touted his dealmaking abilities with foreign leaders. He has previously promised that he would make deals with North Korea and Iran "very quickly" in a possible second term.

North Korea and the U.S. have had talks about removing economic sanctions in exchange for North Korea to pursue a path to denuclearization. Nuclear negotiations between the U.S. and North Korea have been stalled since October 2019.

Trump has developed an unusual and controversial friendship with Kim. The two leaders have shared "beautiful letters" and participated in multiple summits to discuss a possible nuclear deal and other issues.

North Korea has continued to expand its nuclear arsenal during the Trump era. A June report from the Stockholm Peace Research Institute found that North Korea added 10 nuclear weapons to its arsenal in 2019, with the country having 30-40 warheads in total.

The U.S. will likely change its attitude towards North Korea if Biden is elected. The former vice-president has stated that he would only meet with Kim under preconditions.