GOP presidential front-runner Donald Trump has a 10-point lead over his nearest Republican rival in Illinois, which will vote on March 15 along with the all-important states of Florida and Ohio.
Mr. Trump was at 32 percent support in the Chicago Tribune poll out Tuesday, followed by Sen. Ted Cruz of Texas at 22 percent, Sen. Marco Rubio of Florida at 21 percent and Ohio Gov. John Kasich at 18 percent.
The close split among the three candidates behind Mr. Trump illustrates the difficulty of any sort of concerted push to stop him if no candidate is willing to drop out, though some have advocated a contested GOP convention if no candidate ends up securing the necessary 1,237 delegates beforehand.
On the Democratic side, former Secretary of State Hillary Clinton had a sizable 67 percent to 25 percent advantage over Sen. Bernard Sanders of Vermont.