Democratic presidential hopefuls Former Vice President Joe Biden (L), Massachusetts Senator Elizabeth Warren (C) and California Senator Kamala Harris (R) speak during the third Democratic primary debate of the 2020 presidential campaign season hosted by ABC News in partnership with Univision at Texas Southern University in Houston, Texas on September 12, 2019.Robyn Beck | AFP | Getty ImagesDemocratic presidential hopefuls hammered President Donald Trump over his trade war with China in Thursday’s debate as fears grow about the conflict shaking the global economy.The 10 candidates on stage in Houston portrayed an impulsive president with little concrete plan to force Beijing to change what Trump calls unfair trade practices.Both entrepreneur Andrew Yang and former Housing and Urban Development Secretary Julian Castro called the White House’s decisions “haphazard.” Sens. Bernie Sanders, I-Vt., and Kamala Harris, D-Calif., called out the president’s penchant for announcing trade policy through tweet.The pile on shows a field more comfortable with picking apart Trump’s economic conflict with the world’s second largest economy than they were even a few months ago. As companies and consumers show more uneasiness about escalating rounds of tariffs on American and Chinese goods, Democrats came prepared to score points over the president’s trade policy.South Bend, Indiana, Mayor Pete Buttigieg pointed out that Trump had previously argued the small-city official would not be able to negotiate with Chinese President Xi Jinping. “I’d like to see him make a deal with Xi Jinping,” Buttigieg cracked Thursday, referencing Trump’s months long effort to strike a trade agreement with China.Sen. Amy Klobuchar, D-Minn., contended Trump “is treating our farmers and our workers like poker chips in one of his bankrupt casinos.”The attacks come as public opinion polls show voters’ views on the health of the economy and how Trump has handled it have grown worse in recent weeks. This week, Trump temporarily delayed new tariffs on Chinese goods and left the door open to an interim deal with China as he argues the trade conflict has not hurt the U.S.The rhetoric could reflect the economy becoming a better political issue for Democrats, said Elizabeth Simas, a professor of political science at the University of Houston.”I think it’s becoming clear that Trump’s China policies may be a good point of attack for Democrats and so what we’re seeing tonight is the candidates realizing that,” she said.In a statement after the debate, Trump campaign spokeswoman Kayleigh McEnany argued in part that Democrats would kill jobs by reining in the fossil fuel industry. She said Trump’s “record of accomplishment easily eclipses any of these candidates.” The candidates have good reason to highlight the trade war’s effect on farmers, in particular. Iowa, where China’s retaliatory tariffs on crops have done damage, hosts the first-in-the-nation caucus in February.While most of the 10 candidates on stage Thursday eviscerated Trump’s policies, they created distance from one another on trade. Both Yang and Buttigieg said they would not immediately get rid of the president’s duties on Chinese goods.Sanders and Sen. Elizabeth Warren, D-Mass. — whose trade views both overlap with Trump’s — highlighted a U.S. trade policy that they said has harmed workers for years.”Our trade policy in America has been broken for decades and it has been broken because it works for giant multinational corporations and not for much of anyone else,” Warren said.Sanders called American trade policy “disastrous.” He also drew a distinction between himself and the primary’s frontrunner, former Vice President Joe Biden, on trade policy. The senator said he “strongly disagreed” with Biden, highlighting his opposition to the North American Free Trade Agreement, which Biden supported.Biden, like his rivals, said both labor groups and environmentalists need a larger role in trade policy. He also said the U.S. and China need to determine the world’s trading relationships or “China’s going to make the rules of the road.”Subscribe to CNBC on YouTube.