Senate Republicans took a major step toward enacting President Donald Trump’s tax cut agenda and increasing the debt ceiling that could inject a small degree of certainty into financial markets roiled by the president’s tariff policies.

WASHINGTON—A handful of Republican senators broke with President Trump on trade policy, joining with Democrats to pass a resolution aiming to undo the president’s 25% tariff on Canadian imports.The 51-48 vote to approve the measure took place just hours after Trump imposed a 10% baseline tariff on all imports to the U.