Las Vegas (CNN Business) America's negotiating advantage over China in trade talks won't last forever, former CIA Director David Petraeus told CNN Business.

"In the short term, the US has enormous leverage," Petraeus said Thursday during an interview at the SALT Conference in Las Vegas. The retired four-star general pointed to China's need for the United States to keep buying its goods and the country's slowing economy.

Political leaders in Beijing "are very concerned" about Trump's threat to increase tariffs on China as soon as Friday, Petraeus said.

But the 2020 election will soon come into play.

"President Trump has to start worrying about what this does to the economy as he approaches his re-election campaign," said Petraeus, who analyzes geopolitical trends in his role as chairman of the KKR Global Institute.

David Petraeus warned that a prolonged trade war could hurt President Donald Trump's ability to run his 2020 reelection campaign on the economy.

Read More