Stocks extended their sell-off for yet another session Tuesday, and Wharton School professor Jeremy Siegel thinks that the S & P 500 is “absolutely” at risk of going far lower from here. On Tuesday, the S & P 500 , along with the Nasdaq Composite and the Dow Jones Industrial Average , closed lower. The decline came as traders weighed tariff policy uncertainty around Canadian steel and aluminum duties, which President Donald Trump sought to raise to 50% after Ontario Premier Doug Ford decided to charge 25% more on electricity exported to the U.S. By Tuesday afternoon, Ford said he would temporarily suspend the surcharge on power, and White House trade advisor Peter Navarro told CNBC that Trump would not proceed with the threatened tariff hike. At its session low on Tuesday, the S & P 500 slipped 10% from its record close. The benchmark is now toting a year-to-date decline of more than 5%, and it sits 9.4% off its 52-week high. “That’s just a bare touch of a correction,” Siegel said Tuesday on CNBC’s ” Closing Bell .” “Given… each of the last two years, this is not a lot down. We’re still high.” .SPX 1M mountain .SPX, 1-month The professor also said that he thinks there’s “a lot of promise ahead of us” if Trump would sort out his trade policy, saying “a lot of people are just shaking their heads” especially about the president’s tariffs on Canada. “That does not instill confidence,” Siegel continued. “Confidence is your mother’s milk of good economic performance, and these policies are not doing any good for that.” Also on Tuesday, Ukraine agreed to an immediate 30-day ceasefire put forth by the U.S., pending Russian approval of the plan. Siegel said that if the ceasefire deal and the stand-down on tariffs wouldn’t have happened, the market would have seen “another 1,000-point drop day to day.” “It’s clearly this disruptive, destructive – if I should say so – up-and-down trade policy that has really worried the market and sowed uncertainty among consumers and businesses,” he continued. When asked about the White House’s response that “we are in a period of economic transition,” Siegel asserted that “it just doesn’t make sense” both politically and economically. “What are we saying? We’re going to bring 100,000 manufacturing jobs back to the United States and tank the stock market by $20 trillion in the meantime?” he added. “There are unfair trade practices. We want to normalize some of these, but this grand vision, the cost parity is just nowhere near there, and the political parity does not speak anywhere in favor of the Republicans or for the American public.”