John Fund of National Review Online reminds us that Democrats have yet to rally around a single alternative to President Trump.

For a party whose most fervent activists are marinated in identity politics, Democrats could have been expected to gravitate toward a woman or a minority as their presidential candidate. Wrong.

Instead, a new CBS poll, which surveys a large 2,000-person sample of Iowa registered voters heading into that state’s February 3 caucus, shows the top three candidates — Joe Biden, Bernie Sanders, and Pete Buttigieg — are all white guys.

The CBS poll shows a three-way tie among Democrats in Iowa, with Bernie Sanders, Joe Biden, and Pete Buttigieg all tied at 23 percent support.

In New Hampshire, which votes eight days after Iowa, Sanders in another new CBS poll was in the lead, at 27 percent, just ahead of Biden, at 25 percent. …

… Each of the three leading candidates in Iowa are bunched at the top for a reason. Their supporters all believe that their man has the best chance of beating Donald Trump. Joe Biden’s fans see him as an experienced, safe choice. Bernie Sanders’s backers say that only the candidate with the sharpest possible contrast on the issues with President Trump will drive the voter turnout needed to beat the president. Pete Buttigieg’s supporters say the country is looking for a “fresh face,” someone who has no history of Beltway machinations. The 37-year-old Buttigieg, the mayor of South Bend, Ind., certainly provides that. At age 37, he is half the age of President Trump.

But the reason we’re likely to see a long race for the Democratic nomination is that each of the three candidates is having trouble convincing voters outside their base that they can win.