Very much so considering where he started. Good chance he would have won if the race went on a little longer. The same is true for Humphrey in 1968 by the way.
Agreed. Or if Johnson just leaked information that Nixon was sabotaging the peace talks. Something that was actually worse than Watergate.
That was partly Humphrey's fault. He advised Johnson not to release it, thinking he already had the election in the bag by that point. He would later admit it was his biggest regret.
From what I read about the Humphrey campaign was that they were never confident they would win and viewed it as a somewhat uphill battle right until the end. They were behind in polling in Texas and Pennsylvania the whole time, which they ended up winning.
My source:
Johnson did make information available to Humphrey, but at this point Humphrey thought he was going to win the election, so he did not reveal the information to the public. Humphrey later regretted this as a mistake.
For most of the time I actually thought Johnson refrained because he feared Nixon would still win and enter office very damaged.
But I'm sure LBJ would have leaked it, if he himself was the candidate. He wasn't a guy that was playing softball.