Former Secretary of State John Kerry on Wednesday didn't rule out running for president during the 2020 elections.

"I haven't ruled things out," Kerry said in an interview on CNBC's "Squawk Box" when asked about a possible presidential run.

The 74-year-old Democratic former senator, who unsuccessfully ran for president in 2004 against then-GOP incumbent George W. Bush, also said "it's a mistake" to discuss impeachment of President Donald Trump during the midterm elections.

"In two months, we have an election in the country, and that's the most important course correction moment the American people have right now," he said.

Most Democrats have avoided talking about booting Trump from office ahead of the midterms even after Trump's former lawyer Michael Cohen claimed that the president directed him to commit a crime. An impeachment push is risky now, strategists say, as Democrats try to flip at least 23 GOP-held House seats and take control of the chamber.

Kerry also criticized Trump's tariffs on Chinese goods. While Kerry admits the U.S. economy is doing well under the Trump administration, he said any future economic gains will be offset by the trade war.

The Trump administration is attacking what it sees as unfair trade on a number of fronts. A new round of U.S. tariffs on $16 billion worth of Chinese imports kicked in last month, prompting an equivalent retaliation from Beijing.

"If this next round of tariffs is put in place with respect to China, the Chinese I know are prepared to come back and slam us," Kerry said.

He also said low and middle-income American families probably aren't seeing the benefits of a stronger economy, joining other Democrats who say that tax cuts and deregulation benefit wealthy corporations.

Kerry released a memoir last week titled "Every Day Is Extra," which includes details on his five-terms in the senate, his 2004 presidential run, and his four years as secretary of State under former President Barack Obama.