It's time to prepare for OPAL, the first break-in. But which target? There are two possibilities: the DNC, or McGovern headquarters. Remember -- McGovern is the likely nominee, but it's hardly a sure thing. The May 16 primaries in Michigan and Maryland had gone to Wallace, of all people, with Humphrey and McGovern splitting 2nd and 3rd. On May 23 McGovern would win big in Oregon and Rhode Island, and then he would win in California and two other states on June 6...but it's only May 22 now.
Here's Fred Emery:
Liddy's first OPAL target had been McGovern headquarters on Capitol Hill. Politically, it made the most sense in that McGovern now appeared to be the likely Democratic nominee. Thomas Gregory, their McGovern plant, attended the briefing; so did the rest of the team, including the Cuban Americans. Gregory had supplied the headquarters layout and arranged a tour of the office for [Committee to Re-Elect security guy James] McCord, who posed as an out-of-town uncle. McCord recorded the bugs that could be planted within five minutes. The plan was to have Gregory be the last one to leave work in the evening and admit McCord. That plan fell through, however, and Gregory became jittery. Hunt revived the plan that had worked with the Fielding break-in -- making a fake delivery...Again the plan aborted when the McGovern campaign deployed security men.
More on the target. On May 16, the day after Wallace was shot (and the day of the Maryland and Michigan primaries), Haldeman's diary reads: "[Nixon] feels that from a political standpoint this now assures Hubert's nomination, and we talked about that a little." Then, on May 18: "I talked to [Connally] a little about Wallace, he doesn't think Wallace can run as VP on the Democratic ticket. Hubert can't take him, because Wallace is stronger than Hubert, and third party's out of the question because he's come so far in the Democratic Party now that he'd have no reason to go over and diminish his stature. Connally feels that if he's smart, and he thinks he is, that he'll go through the Democratic Convention and then say that he can't take the platform or McGovern or whoever the nominee is so the best thing to do is elect Nixon."
Again, that was May 18. On May 20, Nixon, Haldeman, and others left Washington for a major Moscow summit, not returning until June 1; there's nothing in Haldeman's published diary (paperback edition, as always) about the Democrats now until June 7, the day after the California primary.
So the best evidence I'm aware of, and the logic of the situation, says that the White House was at best uncertain about the likely Democratic nominee on May 22, when Liddy and his operatives were making plans. They may have thought Humphrey the more likely fall opponent. As far as I'm aware there was no plan to hit the Humphrey campaign, for whatever reason, but given the situation, including uncertainty about the party rules and the role that party leaders would play if the nomination became a mess, the Democratic National Committee wasn't actually that nutty of an idea.
Then again, they haven't made that decision yet.