Bernie Sanders, the Vermont senator lighting up Facebook and Twitter feeds from coast to coast, is clearly having his moment. In various polls, he is gaining ground rapidly on Hillary Clinton and continues to draw crowds that most candidates, in this age of political cynicism, can only dream of.

But in the land of data-crunchers, Mr. Sanders is still not very close to becoming the Democratic nominee, let alone the next president of the United States.

Ms. Clinton, who failed so spectacularly to become president in 2008, still holds innumerable advantages over Mr. Sanders, a 73-year-old socialist, experts say. Chief among them is her rock solid grip on nonwhite, moderate and conservative Democrats who will allow the former secretary of state to withstand losses in Iowa and even New Hampshire, where Mr. Sanders’ brand of populism is playing well.

“Hillary Clinton is very, very likely to be the Democratic nominee, not Bernie Sanders. That’s true even if Sanders manages to upset Clinton in both Iowa and New Hampshire,” Larry Sabato, a political scientist at the University of Virginia, wrote today in his nonpartisan “Crystal Ball” newsletter. “The fact is, the key constituencies of the Democratic Party are likely to back Clinton, and big Sanders audiences aren’t going to change that.”

Mr. Sabato argued that recent Democratic and Republican primary history shows that Mr. Sanders will eventually struggle because he lacks so much support from the political establishment. The establishment has a “powerful, formal” role in the Democratic nomination process, Mr. Sabato said, and Ms. Clinton dominates already among support from party leaders and delegates. President Barack Obama, who rose to power after scoring an upset over Ms. Clinton, could count on many more prominent supporters, including Missouri Sen. Claire McCaskill, Illinois Sen. Dick Durbin and then-Virginia Gov. Tim Kane.

Mr. Sanders drew 10,000 people to a recent rally in Madison, WI. and routinely meets standing room-only crowds in the states that he’s visited. But as Mr. Sabato and Nate Silver, the prominent journalist and statistician, pointed out, the early surge of enthusiasm for Mr. Sanders may just be indicative of a candidate’s profile lining up perfectly with the demographics of early voting states. Iowa and New Hampshire are overwhelmingly white, as is Madison.

In Nevada and South Carolina, where the Democratic electorate is far more diverse, Mr. Sanders’ progressive wave may fizzle on the shoreline.

“Democratic caucus-goers in Iowa and Democratic primary voters in New Hampshire are really liberal and really white, and that’s the core of Sanders’s support,” Mr. Silver wrote on his website, FiveThirtyEight, yesterday.

“It just so happens that the idiosyncrasies of the first two states match Sanders’s strengths and Clinton’s relative weaknesses,” he added.

A recent CNN poll showed Mr. Sanders with just 9 percent of support among nonwhite Democrats. A veteran of the civil rights movement, Mr. Sanders has vowed to campaign aggressively for minority votes. Yet Ms. Clinton’s commanding lead among black and Latino voters is no fluke, and it may take more than stumping, television appearances with Rev. Al Sharpton and a few campaign ads for Mr. Sanders to make significant headway.

Mr. Obama, as the first African-American to become president, had the ability to erode Ms. Clinton’s minority support. Mr. Sanders, as a white man, is not history-making. (Ms. Clinton, who could become the first woman to win the Democratic nomination, also leads among female voters and if Mr. Sanders doesn’t close this gender gap, he will lose.)

Nate Cohn in the New York Times wrote yesterday that Mr. Sanders will have to contend with a rank-and-file Democratic electorate that is still a lot less liberal than he is, even given that Democratic voters are tilting more left on social and fiscal issues.

“To close the gap with Mrs. Clinton, Mr. Sanders will need to make big gains among less liberal Democratic primary voters,” Mr. Cohn wrote. “Nearly half of the Democratic primary electorate is moderate or even conservative.”

In 2008, Ms. Clinton’s path to the presidency was threatened on at least two fronts. Nonwhite voters could flock to Mr. Obama and more moderate, white southern and Midwestern Democrats could look to John Edwards, the telegenic North Carolina senator with his own populist message.

So far, Mr. Sanders hasn’t shown he can replicate Mr. Obama’s winning coalition. Even with his impressive $15 million haul, most of it from small donors, Mr. Sanders will not be able to raise nearly as money as Ms. Clinton or even Mr. Obama seven years ago. In the smaller, early voting states, he can survive.

In New York, California, Michigan, Ohio, Florida and elsewhere, money starts to matter.

“It would be embarrassing for Clinton to lose or have close calls in Iowa and New Hampshire, but they are not the be-all of the nominating season,” Mr. Sabato wrote.