Biden ahead of Sanders in Michigan primary, but there are reasons to distrust recent poll

Former Vice President Joe Biden is leading U.S. Sen. Bernie Sanders in the most recent poll of likely Democratic primary voters in Michigan.

The Detroit News/WDIV-TV survey shows Biden edging out Sanders, 29% to 22.5%.

But there are a few significant reasons to be skeptical of the poll. First, former New York Mayor Mike Bloomberg, who dropped out of the race Wednesday and endorsed Biden, garnered 10.5% in the poll. Given Bloomberg’s centrism and endorsement, it would seem like Biden has the most to gain from the billionaire’s exit. But there’s no data to back that up.

Second, Elizabeth Warren received 7% in the poll. It’s entirely possible she, too, will drop out of the race, leaving another chunk of the electorate to choose between Sanders and Biden. Warren’s progressive platform is closer to Sanders’ than Biden’s.

Perhaps most significantly, Sanders defeated Hillary Clinton in Michigan’s Democratic primary in 2016, even though polls showed her leading the race by 21 percentage points. At the time, Nate Silver, a popular political statistician and editor-in-chief of FiveThirtyEight, said it would be “among the greatest polling errors in primary history” if Sanders won in Michigan. The polls underestimated how many young voters would support Sanders.

Then there are the endorsements that have come after the poll. Michigan Gov. Gretchen Whitmer, who initially said she would not endorse a candidate during the Democratic primary, told reporters Wednesday that she may change her mind.

"A lot of things have changed in the last 72 hours," she said. "If I get involved, you'll probably hear from me in short order."

She likely would support Biden.

On Wednesday, former Michigan Gov. Jennifer Granholm endorsed Biden.

The Detroit News/WDIV-TV poll surveyed 600 likely Democratic primary voters from Feb. 28 to March 3. The margin of error is 4 percentage points.

Another recent poll found the top five Democratic primary candidates leading President Donald Trump in a head-to-head matchup.

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