In his chapter on ‘Hope” in Dylan’s Visions of Sin, Ricks refers to “Can’t Wait” as one of Bob’s “how much longer” songs.  From the title, how much longer he can’t wait clashes with the ending of just about every stanza when he either says “And” or “But” “I don’t know how much longer I can wait.”  Can/Can’t what’s the difference, right?  Well, when you say you can’t wait for something eager anticipation is involved, saying you can wait implies a kind of take or leave it, leaning on the leave it.

The first verse includes another clash, a singer trying to walk the line (side to side, horizontal movement) surrounded by people all around going up and down (vertical movement):

I can’t wait, wait for you to change your mind
It’s late, I’m trying to walk the line
Well, it’s way past midnight and there are people all around
Some on their way up, some on their way down
The air burns and I’m trying to think straight
And I don’t know how much longer I can wait

The “can’t wait” seems more literal–he literally can’t wait–there’s an urgency, but not one tied to anticipation.  Something’s about to happen.  It’s way past midnight–and people going up or down suggest a waiting for judgment that’s a result of the tolling of the midnight bell.  The burning air is ominous, portending a descent rather than an airlift, threatening attempts to walk a line.

It’s  a song structured with terminal rhymes, each end of the line rhymes, and this song seems about being at the end of the line (walking a line until it ends) or one’s line, or rope, though if the line’s long enough maybe he’ll just have to wait, or we will; it’ plays out as a long song, can’t wait for it to end . . . how much longer . . . or can’t wait for the end, can’t wait, can wait.

Played live 210 times over a 22 year period (1997-2019), the song’s had a good run. It seems Bob can’t wait to play it at every concert lately. Here’s one performance from the late 90’s most likely, admired by many listeners: