Last Updated Jun 8, 2016 2:13 PM EDT
Sen. Claire McCaskill, D-Missouri, has some advice for Bernie Sanders, now that Clinton has the delegates needed to secure the party's nomination: step aside and help the party's first female nominee fight against Donald Trump.
Specifically, the Missouri senator said Sanders can play a crucial role in helping Clinton make inroads with young voters, one of her weakest constituencies and his strongest constituencies during this primary campaign.
"Bernie has to be a part of that," Senator McCaskill said in an interview today on CBS This Morning.
McCaskill also took issue with some of the actions Sanders has taken--like urging superdelegates to support him on the floor of the Philadelphia convention in July. She argues that Sanders is violating the will of the people he claims to champion. Nationwide, Clinton has received millions more votes than Sanders and has won a majority of Democratic primary voters.
"I think for Bernie, the irony of this is, he began the campaign saying we need to let the people decide, not the superdelegates. Now he's ending the campaign saying never mind what the people decided, we need to have the super delegates decide. I don't think that's gonna work," McCaskill said.
At the same time, McCaskill -- one of the first members of Congress to support Clinton's presidential bid -- said the Democratic Party should give her Vermont colleague time to make his decision.
"He's elevated the debate of our party. I think we are stronger because of it and I think, over time, over the next few weeks, I think this well all come together because I know he cares deeply about making sure that Donald Trump's finger is never near the button," she said.
In an interview on CNN, Vice President Joe Biden also said he thinks the timing of Sanders' departure should be "his call."
"It's clear we know who the nominee is going to be," he said. "I think we should be a little graceful and give him the opportunity to decide on his own."
McCaskill watched last night's votes -- from the states of California, Montana, New Jersey, New Mexico, North Dakota -- roll in alongside her female colleagues from the Senate, she said. Thirteen of the Senate's 14 female Democrats have supported Clinton in her presidential bid. (The only female Democrat in the Senate who did not endorse Clinton is Massachusetts Senator Elizabeth Warren, a staunch progressive whose name is now being floated as a potential vice presidential pick, to appeal to the far-left wing of the party.)
"We all kind of looked at each other trying to keep from busting out in a big grin because all of us knew what yesterday meant in terms of the history of our country and the struggles that so many women have gone through and I thought her speech last night was particularly uplifting in recognizing what our country really is all about," McCaskill said.
She's hopeful that voters will ultimately elect Clinton, given that this is a "different kind of election."
"It's whether or not we're going to put into the Oval Office someone who is vulgar, and makes frequent racist comments, who makes it up as he goes along, who is risky and reckless with what he says, who has been a buffoon in many instances and would be a buffoon on the world stage -- versus someone who is strong and steady and capable," she said.