AFP/Getty Images
Now playing
01:44
Bernie Sanders wins case to allow 17-year-olds vote
bernie sanders still feels the bern origwx allee_00011828.jpg
bernie sanders still feels the bern origwx allee_00011828.jpg
Now playing
01:56
Bernie Sanders still feels the bern
bernie sanders democrats trump bannon bts_00000924.jpg
bernie sanders democrats trump bannon bts_00000924.jpg
Now playing
01:18
Sanders: Democrats will work with Trump if ...
Republican presidential candidate Donald Trump addresses a rally against the Iran nuclear deal on the West Lawn of the U.S. Capitol September 9, 2015 in Washington, D.C.
Chip Somodevilla/Getty Images North America/Getty Images
Republican presidential candidate Donald Trump addresses a rally against the Iran nuclear deal on the West Lawn of the U.S. Capitol September 9, 2015 in Washington, D.C.
Now playing
02:40
Can Trump be trusted with nuclear weapons?
SANTA MONICA, CA - JUNE 07:  Democratic presidential candidate Senator Bernie Sanders (D-VT) greets supporters at an election-night rally on June 7, 2016 in Santa Monica, ia. Hillary Clinton held an early lead in today's California primary.  (Photo by Scott Olson/Getty Images)
Scott Olson/Getty Images
SANTA MONICA, CA - JUNE 07: Democratic presidential candidate Senator Bernie Sanders (D-VT) greets supporters at an election-night rally on June 7, 2016 in Santa Monica, ia. Hillary Clinton held an early lead in today's California primary. (Photo by Scott Olson/Getty Images)
Now playing
02:20
Five moments from Bernie Sanders' improbable run
security scan
DHS
security scan
Now playing
03:04
Fear, anger over potential 'Muslim registry'
CNN
Now playing
02:05
Bernie Sanders says he will work with Donald Trump
Student slams Clinton
Youtube/David K
Student slams Clinton
Now playing
01:15
Student bashes Clinton ... at Clinton event
dnc convention roll call brother larry sanders sot _00012118.jpg
dnc convention roll call brother larry sanders sot _00012118.jpg
Now playing
01:23
Bernie Sanders gets emotional at DNC roll call
Sen. Bernie Sanders speaks to reporters in Oakland, California. May 30, 2016.
CNN
Sen. Bernie Sanders speaks to reporters in Oakland, California. May 30, 2016.
Now playing
01:36
Secret Service rush stage at Bernie Sanders rally
Bernie Sanders takes the stage at the DNC Convention
CNN
Bernie Sanders takes the stage at the DNC Convention
Now playing
01:00
Bernie Sanders takes the DNC stage, crowd goes crazy
Bernie Sanders speaks to members of the press before being introduced at the Allen Temple Baptist Church in Oakland, California on May 30, 2016.
JOSH EDELSON/AFP/Getty Images
Bernie Sanders speaks to members of the press before being introduced at the Allen Temple Baptist Church in Oakland, California on May 30, 2016.
Now playing
02:56
It's 'Bernie or bust' for some Sanders supporters
U.S. Sen. Bernie Sanders (I-VT) speaks during a campaign rally with democratic presidential nominee former Secretary of State Hillary Clinton at University of New Hampshire on September 28, 2016 in Durham, New Hampshire.
Justin Sullivan/Getty Images
U.S. Sen. Bernie Sanders (I-VT) speaks during a campaign rally with democratic presidential nominee former Secretary of State Hillary Clinton at University of New Hampshire on September 28, 2016 in Durham, New Hampshire.
Now playing
02:51
Sanders walks fine line on Clinton hacked audio tape
Bernie sot 3
CNN
Bernie sot 3
Now playing
02:23
Sanders' new message to his supporters
Getty Images
Now playing
03:20
Who voted for Sanders and can Trump win them over?
FAIRFIELD, CA - JUNE 03: Democratic presidential candidate, U.S. Sen. Bernie Sanders (D-VT) speaks during a campaign rally at Cloverdale Municipal Airport on June 3, 2016 in Cloverdale, California. Five States including California will hold the final Super Tuesday primaries next week. (Photo by Ramin Talaie/Getty Images)
Ramin Talaie/Getty Images
FAIRFIELD, CA - JUNE 03: Democratic presidential candidate, U.S. Sen. Bernie Sanders (D-VT) speaks during a campaign rally at Cloverdale Municipal Airport on June 3, 2016 in Cloverdale, California. Five States including California will hold the final Super Tuesday primaries next week. (Photo by Ramin Talaie/Getty Images)
Now playing
02:07
What the end of the Sanders primary campaign looks like

Story highlights

"Well, I don't know where he was when I was trying to get health care in '93 and '94," Clinton said of Sanders

The problem: Sanders attended an event with her to push health care reform in 1993 and introduced his own single-payer health care plan in March of that year

Watch CNN’s Democratic Town Hall, co-hosted by TV One, Sunday at 8 p.m. ET.

St. Louis CNN —  

Hillary Clinton on Saturday questioned where Vermont Sen. Bernie Sanders was when she was fighting for expanding health care as first lady in 1993 and 1994.

“We are going to pull together and stay together and stand up against those powerful forces. And I always get a little chuckle when I hear my opponent talking about doing it,” Clinton said at an event here. “Well, I don’t know where he was when I was trying to get health care in ‘93 and ‘94, standing up the insurance companies, standing up against the drug companies.”

The problem: Sanders attended an event with her to push health care reform in 1993 and introduced his own single-payer health care plan in March of that year. And Clinton wrote him a hand-written thank you note for his work on the issue in 1993.

Some of Sanders’ aides quickly tweeted a photo on Saturday of Sanders standing behind Clinton at an event at Dartmouth College on December 7, 1993.

“I am grateful that Congressman Sanders could join us today from Vermont,” Clinton said at the event.

Jennifer Palmieri, Clinton’s communications director, argued after Clinton knocked Sanders that the video of the then-Vermont congressman standing behind the first lady “proves our point.”

“Hillary Clinton was out in front. Senator Sanders was in the background. She is the one that took the slings and arrows from the health care industry,” Palmieri said, adding later that in the video pushed by the Sanders campaign, “He is literally standing behind her, she is literally the one out front, as she was 20-25 years ago.”

Palmieri added, “If you look at the public record, I do not think you are going to find a lot of evidence of senator sanders working very hard to push for this health care bill to pass. She is the one who worked.”

Sanders introduced the “Health Care as a Right for All” bill on March 4, 1993, in the middle of Clinton’s push for health care reform. The legislation would have created a single-payer universal health care system, something Clinton entertained but eventually did not include in her health care push.

Clinton wrote a hand-written thank you to Sanders for his work on what came to be known as Hillarycare, the Clinton White House’s efforts to pass comprehensive healthcare reform that was spearheaded by the then-first lady.

“To Bernie Sanders with thanks for your commitment to real health care access for all Americans and best wishes,” Clinton wrote on a picture of the two talking. The picture includes a note and is signed “Hillary Rodham Clinton” and dated 1993.

Clinton’s knock against Sanders on Saturday came moments after the former secretary of state hit Sanders for “misrepresenting my record and his own.”

“That is his choice,” Clinton said of Sanders.

Clinton and Sanders are locked in an all-out sprint to contests in Florida, Ohio, Missouri, Illinois and North Carolina on Tuesday. Sanders has some momentum coming out of Michigan, where he unexpectedly beat Clinton by 2% earlier this week.

Clinton aides are confident they will win in Florid and North Carolina, but are worried about “toss ups” in Ohio, Illinois and Missouri, states that are more economically and demographically similar to Michigan.