Even before the Nevada caucuses put Vermont Sen. Bernie Sanders in a commanding position among the Democratic presidential field, he was leading with Illinois voters, a statewide poll shows.

The Simon Poll, commissioned by the Paul Simon Public Policy Institute at Southern Illinois University ahead of the March 17 primary, found Sanders favored by 22% of likely Democratic voters, followed by former New York City Mayor Michael Bloomberg with 17%, and former Vice President Joe Biden with 14%. Former South Bend Mayor Pete Buttigieg was at 13%, Minnesota Sen. Amy Klobuchar at 8% and Massachusetts Sen. Elizabeth Warren at 6%.

Andrew Yang, who has since dropped out of the race, and businessman Tom Steyer each had 1%.

Charlie Leonard, visiting professor at the Simon institute, said there was nothing “particularly surprising” about the results, given what already played out in other states. While the results provide a “snapshot” of voter sentiment, he said it’s also “difficult to read too much” into the numbers.

Part of the reason, he said, was the sample margin of error. Customer Research International of San Marcos, Texas, surveyed 1,000 people Feb. 10-17 for the poll and only 821 identified themselves as likely voters. Some did not say if they would take a Democratic or Republican ballot. Leonard concluded the presidential preference question went only to likely voters of each party – 475 Democrats and 232 Republicans. The margin of error among Democrats in that calculation is plus or minus 4.5 percentage points, while among Republicans it is 6.4 percentage points.

John Jackson, visiting professor of political science at the Simon institute, said that he doubts the Nevada caucus outcome would have had a significant effect on the Illinois poll numbers, but he did say last week’s debate “might have shaved some margin off” Bloomberg’s numbers, though he still thinks the former New York mayor would have come in second.

“He’s still spending money like crazy,” Jackson said of Bloomberg, who has flooded the airwaves with advertising and opened offices in the state.

Leonard said Illinois’ primary could play a role in the national presidential picture on the Democratic side. The Illinois vote comes after several other contests, including Super Tuesday primaries in more than a dozen states on March 3.

“Every primary henceforth is going to bring a little more clarity to the presidential race,” Leonard said. “I think Super Tuesday will decide a lot, and Illinois’ primary will come in behind that and maybe do some consolidating and mopping up.”

A Chicago Tribune story published online Monday raised questions about the Simon Poll’s methodology and accuracy. For example, the Tribune reported, the 1,000 registered voters who took part in the poll included 56% men and 44% women, but the federal census shows a majority of the state’s population is female. The newspaper also reported that only a quarter of the poll’s Democratic votes came from Chicago, while in 2016, Chicago accounted for 35% of the state’s Democratic primary turnout.

Jackson said there’s no evidence that the way the poll was conducted skewed results. “We think our basic findings are essentially accurate,” he said.

On the Republican side, the poll only mentioned two presidential candidates — President Donald Trump and former Massachusetts Gov. William Weld. While Weld is still in the race nationally, he did not file to run in Illinois. The only primary competition Trump faces on the Illinois ballot is from little-known Rocky De La Fuente of San Diego. In the Simon poll, Trump received 89% to 4% for Weld.

Overall, 39% of Illinois voters approved of Trump's job performance to 58% who disapproved. Among Republicans, approval for the president was 87% to 12% disapproval. Among Democrats, 92% disapprove and 7% approve. Among independents, 43% approve and 52% disapprove.

All 1,000 voters were asked their views of Gov. JB Pritzker, who is in the middle of a four-year term, and U.S. Sen. Dick Durbin, D-Illinois, of Springfield, who is running for a new six-year term but is unopposed in the primary.

The poll found 51% of respondents approved of Pritzker’s job performance and 38% disapproved. Among Democrats, Pritzker’s approval-disapproval was 77% and 14% respectively. Among Republicans, 73% disapproved and 20% approved. Independents split, with 44% approving and 43% disapproving.

The Pritzker overall approval rate is up 11 points from a 2019 Simon Poll, when the governor had been in office just two months. At that time, he received 40% approval to 38% disapproval.

Durbin received 52% approval overall to 36% disapproval. Among Democrats, approval versus disapproval for Durbin was 79% to 12%. Seventy percent of Republicans disapprove of his job to 20% who approve.

Bernard Schoenburg: 217-788-1540, bernard.schoenburg@sj-r.com, @bschoenburg