since I hadn't heard of Graham's remarks anywhere, nor a solid call for any expansion plan, I did a quick search.
Most recent stories (I did not go very deeply into it) were May reprints of March "news".
But I did see quotes from some leading libs/dems speaking out:
...Others aren’t willing to go there just yet. Sen. Cory Booker (D-N.J.), a liberal running for president, seemed cool to the idea.
“I’m open to these kind of conversations, but I really caution people about doing things that become a tit for tat throughout history,” Booker said in an interview. “So when the Democrats expand it to 11, 12 judges, when Republicans have it, they expand it to 15 judges.”
“I share the legitimate outrage following Majority Leader McConnell’s demolition of our responsibility to advise and consent on judicial nominations. But we must not accept that our only course of action is to join in that demolition,” said Sen. Michael Bennet (D-Colo.), who is mulling a presidential run.
And 2020 candidate Sen. Amy Klobuchar (D-Minn.) was equally cautious: “You always want to look at all ideas, but I think right now the most reasonable thing is to win the elections and to try to stop the bad judges.”