Millennial voters would overwhelmingly back Bernie Sanders in a head-to-head contest with presumptive Republican presidential nominee Donald Trump, but the contest between Trump and likely Democratic nominee Hillary Clinton is much closer, a new poll finds.  According to a CBS News/New York Times national survey released Thursday, Sanders would best Trump 66% to 25% among voters between the ages of 18 and 29, indicating that the robust support the Vermont senator has received from young voters in his primary bid would extend to the general election. But Clinton only leads Trump 47% to 34% among those voters — a sign she may struggle to win over some of Sanders' most fervent supporters.  Millennials give Hillary Clinton only tepid support over Donald Trump  Supporters of Democratic presidential candidate Hillary Clinton arrive to attend a primary night event during Pennsylvania's primary election on April 26, 2016 in Philadelphia, Pennsylvania. Voters cast ballots in five northeastern states, with frontrunners Hillary Clinton and Donald Trump both looking to overwhelm their respective Democratic and Republican rivals in the race for the White House / AFP / EDUARDO MUNOZ (Photo credit should read EDUARDO MUNOZ/AFP/Getty Images)  Six-year-old Kayla Johnson (C) her mother Andrea (L) and friend London Walters (R) react as U.S. Democratic presidential candidate Hillary Clinton enters the Garrick-Boykin Human Development Center at Morris College in Sumter, South Carolina, February 24, 2016. REUTERS/Randall Hill  TOPSHOT - A car with the face of Democratic presidential candidate Bernie Sanders drives past a supporter of Democratic presidential candidate Hillary Clinton on Broad Street during Pennsylvania's primary election on April 26, 2016 in Philadelphia, Pennsylvania. Voters cast ballots in five northeastern states, with frontrunners Hillary Clinton and Donald Trump both looking to overwhelm their respective Democratic and Republican rivals in the race for the White House. / AFP / EDUARDO MUNOZ ALVAREZ (Photo credit should read EDUARDO MUNOZ ALVAREZ/AFP/Getty Images)  Artist Gretchen Baer of BisBee, Arizona, stands next to the "Hillcar", a car she painted and decorated in support of Democratic U.S. presidential candidate Hillary Clinton, as she stands on a street in the Manhattan borough of New York City, U.S. April 18, 2016. REUTERS/Mike Segar EDITORIAL USE ONLY. NO RESALES. NO ARCHIVE  FILE - In this April 19, 2016, photo, supporters of Democratic presidential candidate Hillary Clinton celebrate at her New York primary campaign headquarters. With six months to go, the U.S. election campaign has boiled down to an unprecedented contest that could transform America's role in the world. Democrat Hillary Clinton, a fixture on the political stage for a quarter century, is set to face Donald Trump, a brash billionaire real estate mogul who has never held elected office. (AP Photo/Kathy Willens, File)  Supporters listen to Democratic presidential candidate Hillary Clinton speak during a rally at Louisville Slugger Field's Hall of Fame Pavilion in Louisville, Ky., Tuesday, May 10, 2016. (AP Photo/Patrick Semansky)  Supporters listen to Democratic presidential candidate Hillary Clinton campaign at East Los Angeles College in Los Angeles, Thursday, May 5, 2016. (AP Photo/Damian Dovarganes)  Democratic presidential candidate Hillary Clinton takes a selfie with a supporter after a speaking at a rally at Louisville Slugger Field's Hall of Fame Pavilion in Louisville, Ky., Tuesday, May 10, 2016. (AP Photo/Patrick Semansky)  Supporters of Democratic U.S. presidential candidate Hillary Clinton attend a "Women for Hillary" campaign rally in the Manhattan borough of New York City, U.S. April 18, 2016. REUTERS/Mike Segar  A supporter fans herself as Democratic U.S. presidential candidate Hillary Clinton speaks at Southwest College in Los Angeles, California, United States, April 16, 2016. REUTERS/Lucy Nicholson  A supporter holds up an action figure of Democratic U.S. presidential candidate Hillary Clinton before Clinton spoke at Southwest College in Los Angeles, California, United States, April 16, 2016. REUTERS/Lucy Nicholson  A supporter for Democratic presidential candidate Hillary Clinton boos at the mention of Donald Trump as Clinton speaks at Carnegie Mellon University on a campaign stop, Wednesday, April 6, 2016, in Pittsburgh. (AP Photo/Keith Srakocic)  A supporter of Democratic presidential candidate Hillary Clinton holds a sign during a campaign event featuring Clinton at the Riverside Ballroom in Green Bay, Wis., Tuesday, March 29, 2016. (AP Photo/Patrick Semansky)  OAKLAND, CA - MAY 06: Supporters look on as democratic presidential candidate former Secretary of State Hillary Clinton speaks during a campaign rally on May 6, 2016 in Oakland, California. Hillary Clinton is campaigning in California ahead of the State's presidential primary on June 7th. (Photo by Justin Sullivan/Getty Images)  Planned Parenthood and Democratic presidential candidate Hillary Clinton supporters looks to the stage during the National Anthem during a Clinton campaign event at Rainier Beach High School in Seattle, Tuesday, March 22, 2016. (AP Photo/Carolyn Kaster)  Democratic presidential candidate Hillary Clinton takes photos with supporters in the audience after speaking during a campaign event at Carl Hayden Community High School in Phoenix, Monday, March 21, 2016. (AP Photo/Carolyn Kaster)  NEW YORK, NY - MARCH 2: A members of the Laborers International Union of North America (LiUNA) and Hillary Clinton supporters outside Hillary Clinton rally at the Jacob Davits Center in New York, New York on March 2, 2016. Photo Credit: Rainmaker Photo/MediaPunch/IPX  Supporters cheer for Democratic presidential candidate Hillary Clinton while she speaks at a campaign event at George Mason University in Fairfax, Va., Monday, Feb. 29, 2016. (AP Photo/Molly Riley)  U.S. Democratic presidential candidate Hillary Clinton greets supporters after a town hall meeting at Cumberland United Methodist Church in Florence, South Carolina February 25, 2016. REUTERS/Jonathan Ernst TPX IMAGES OF THE DAY  Clinton does best among voters between 30 and 44, with whom she leads 56% to 32%. But even among that group, Sanders does better, thumping Trump 61% to 28%. The former secretary of state narrowly trails Trump among voters over the age of 45.  Other polls have suggested Clinton would do better among millennials. A Harvard Institute of Politics survey found in April that Clinton would defeat Trump 61% to 25% with voters 18 to 29 years old.  The big picture: Overall, Clinton leads Trump 47% to 41% nationally, according to the CBS/Times poll, though that lead is down from her 50% to 40% advantage in April — a result that dovetails with a tightening race in other surveys. According to the RealClearPolitics polling average, Clinton's lead over Trump has narrowed to just 46% to 43%, down from about 50% to 39% in late March.  Sanders, meanwhile, led Trump 51% to 38% in the CBS/Times poll, while the RealClearPolitics average finds the senator with a 51% to 39% advantage over the Manhattan real estate tycoon.  As Clinton looks to seal the nomination after the California primary on June 7, her prospects for uniting the party look a bit better than then-Sen. Barack Obama's did eight years ago. At a similar point in 2008, the CBS/Times poll found that 60% of Clinton's supporters were prepared to cast ballots for Obama after the pair's bruising primary battle. This time, 72% of Sanders voters say they'll pull the lever for Clinton — but resistance may be greatest among the youngest.  More from Mic.com: This Dead Woman Summed Up How So Many Feel About a Donald Trump v Hillary Clinton Election Elizabeth Warren Claps Back at Donald Trump: Voters "Are Smarter Than You Think" One of Donald Trump's Possible Supreme Court Picks Has Mocked Him on Twitter All Year
A new poll suggests the race between presumptive GOP nominee and Clinton would be very close among millennial voters.