Los Angeles(CNN) When Hillary Clinton became the first woman to clinch the nomination of a major political party, she marked the moment as a milestone. But many of the millennial women supporting Bernie Sanders weren't celebrating this week.
"To every little girl who dreams big: Yes, you can be anything you want—even president. Tonight is for you. --H," the candidate tweeted Tuesday evening. But a number of young women who attended Sanders' election night rally in Santa Monica didn't even bother to listen to her speech.
One of Clinton's most fascinating challenges during her primary campaign has been her struggle to excite young women, particularly millennials. Taking a look back at the primary campaign in its totality, that generational divide was huge.
CNN's Polling Director Jennifer Agiesta analyzed the age and gender breakdown in 27 states where CNN conducted exit and entrance polls during the primaries -- and found that overall, Clinton led Sanders 61% to 37% among women.
But when she analyzed the age and gender breakdown across those 27 states, Sanders led Clinton by an average of 37 percentage points among women 18 to 29 -- a stunning result given Clinton's emphasis on the historic nature of her candidacy.
Female firsts in politics
Hillary Clinton, a former first lady, U.S. senator and secretary of state, claims her place in history on Tuesday, July 27, after becoming the Democratic Party's nominee for U.S. President. She would be the first woman in U.S. history to lead the ticket of a major political party.
Elizabeth Cady Stanton was the first woman to run for a seat in the U.S. House of Representatives. She was a leader of the suffragette movement along with Lucretia Mott and Susan B. Anthony. She was also the editor of the feminist magazine "Revolution."
In 1916, Jeannette Rankin was the first woman to be elected to the U.S. House of Representatives. The Republican from Montana was the only member of Congress to vote against U.S. entry in both World War I and World War II.
Feminist reformer Victoria Claflin Woodhull was the first woman to run for U.S. President from a nationally recognized ticket. She was the candidate of the Equal Rights Party in 1872.
Frances Perkins was the first woman to serve as a member of the President's Cabinet. She was appointed labor secretary by President Franklin D. Roosevelt in 1933.
Shirley Chisholm, a Democrat from New York, was the first African-American woman to be elected to the U.S. House of Representatives. She was elected in 1968.
Sandra Day O'Connor was the first woman to be appointed to the U.S. Supreme Court. She was appointed by President Ronald Reagan in 1981.
In 1984, Geraldine Ferraro became the first woman to run on a major party's national ticket. She was Walter Mondale's running mate.
U.S. Rep. Ileana Ros-Lehtinen, a Republican from Florida, was elected in 1989. She is the first Hispanic woman and Cuban-American to be elected to the U.S. House of Representatives.
Carol Moseley Braun, a Democrat from Illinois, was the first African-American woman to be elected to the U.S. Senate. She served from 1993 to 1999.
Dee Dee Myers was the first woman to serve as White House press secretary. She was appointed by President Bill Clinton and held the position from January 1993 to December 1994.
Madeleine Albright was the first woman to serve as U.S. secretary of state. She was appointed to the position by President Bill Clinton in 1997.
U.S. Sen. Tammy Baldwin, a Democrat from Wisconsin, is the first openly gay woman to be elected to Congress. She was elected to the House in 1999 and to the Senate in 2012.
House Minority Leader Nancy Pelosi, a Democrat from California, is the first woman to lead a party in Congress.
Sonia Sotomayor is the first Hispanic woman to serve on the Supreme Court. She was nominated by President Barack Obama in 2009.
U.S. Sen. Mazie Hirono, a Democrat from Hawaii, is the first woman of color to serve in both chambers of Congress. Hirono was elected to the House in 2007 and to the Senate in 2012.
Support for Clinton rose as the age of women went up. Women who were 30 to 39 were more likely to support Clinton by an average of 53% for Clinton and 46% for Sanders. And among older women, Clinton dominated Sanders by huge double-digit margins.
At Clinton rallies, a number of older women were critical of the younger generation, arguing that they are not backing the former secretary of state's candidacy because they never faced the kind of discrimination that women of Clinton's era did.
But in interviews during the final days of the California campaign, many young women at Sanders rallies said they would never vote on the basis of gender. They cited trust and integrity issues as the reason they weren't voting for Clinton, and said their support for Sanders' platform and policies trumped any notion that they should back a candidate angling for a historic first.
Among the "Bernie or Bust" contingent, some said they planned to stay home; others said they would vote for Green Party nominee Jill Stein.
Clinton's challenge of closing the generational gap may become far easier now that she's in a one-on-one race with Donald Trump, who is viewed unfavorably by a large majority of American women.
But many millennial women supporting Sanders are still holding out hope for a contested convention, and she may have hard work ahead to win them over and turn them out in November.