(Note: This essay was written in response to an item in WebbWrap)

I'm not at all convinced the Democrats want to pack the Court if Judge Barrett is confirmed. Their reluctance to take a public yes-or-no stand is exactly the approach I'd take if I wanted to avoid her confirmation by convincing a couple Republicans to vote down the nomination in order to avoid Court packing.
Taking a firm "yes" stand risks alienating moderates in the upcoming election. It also guarantees you'll alienate the liberal base if you aren't really willing to go there (and I'm not convinced there will be 50 Democratic Senators willing to go there, which means they can't even let it come up for a vote).

Taking a firm "no" stand, on the other hand, throws away the best (arguably only) leverage they have on Judge Barrett's confirmation. The only other possibility is a mild public preference against filling the seat now. Unless that's a strong preference in a couple states with tight Senate races, that doesn't seem to provide any real leverage.

I'd play coy in public while privately strong-arming a couple Republican Senators I think might be swayed, pointing out that wrt the Court, it's the Republicans who have taken all the (at least reasonably recent) might-makes-right actions: refusing even to hold hearings on Merrick or any other Obama nominee in the last year of his term, eliminating the filibuster, ignoring the principles they espoused four years ago to rush through an appointment in the last year of Trump's (current) term.

I'd ask how many times the Republicans can expect to use the "because we can" argument before the Democrats return the favor.

I'd (rightly) claim to be horrified at the prospect of expanding the Court for partisan reasons but point out that the party's base will vote out every Incumbent Democratic Senator - or worse yet, just stay home - in 2 years if the Democrats take control and don't take this option.

I'd argue that the only ones who can avoid this are the current Republican Senators and implore them to think of the long-term good of the Senate, the Court, and the country before confirming Judge Barrett's nomination and forcing our hand.

And if I were Biden, I'd mention that one of the reasons I don't like Barrett as a Justice is that I think the Court already has enough weight on the liberal & conservative edges and that I'd personally like to see the next appointment go to someone more likely to be a "swing vote."

On the surface, it looks like Biden & Harris want to pack the court if they're elected with a Senate majority - and maybe they do - but that isn't the necessary conclusion from the facts at hand. I think they're trying to avoid the question entirely.