I'm way behind, and it's time to catch up.
Here's what you need to know. Over the winter of 1971-1972, Richard Nixon still looked vulnerable. Things were bending in the right direction for him, but as late as January 7-10 Gallup still had him at 49%. which was about where he had been since March of 1971. Not in deep trouble, but not yet safe, either. Meanwhile, the Democrats had three formidable looking candidates. The active frontrunner was Ed Muskie, who had impressed everyone as a VP candidate in 1968 and seemed dangerous. Lurking behind him was Hubert Humphrey. Humphrey had lost to Nixon by a whisker in 1968, and if he was to capture the nomination again one would assume that his party would be more unified and his convention a better kick-off; neither could possibly be any worse, could they? And still out there was the biggest threat of all, Ted Kennedy, whose brothers had been martyred so recently. Yes, Chappaquiddick in 1969 was a problem, but the Kennedy name was still magic. Nixon was right to be concerned about all three of these foes.
The New Hampshire primary that year wasn't until March. And almost no one understood the importance of the reforms which made a late entry difficult and a candidate winning without contesting primaries, as Humphrey had done in 1968, more or less impossible. So it took long into spring for Nixon's men to understand that Kennedy really wasn't going to be a factor, and dream opponent George McGovern didn't clearly clinch things, as it turned out, until the convention in mid-July (indeed, he didn't have it won at all until he beat Humphrey in California on June 6, and then he had to win a couple of credentials fights at the convention to seal it).
Remember, too, that as of January 1972 Republicans had only won three presidential elections since 1928: two with a national hero at the head of the ticket, and one squeaker with the Democrats divided three ways (that is, with George Wallace on the ballot and with liberals furious at the party for most of the campaign); Democrats of course still controlled by Houses of Congress and had in almost every election since the New Deal.
In other words, Nixon was quite right to consider re-election extremely uncertain as of January 1972.
How did Nixon deal with all this uncertainty? He demanded information -- and his men demanded information. Information about what the Democrats were up to. Lots of information. More information.
And thus it was that the Committee to Re-Elect the President needed an upgrade in information gathering, and after a false start, wound up -- on the recommendation of John Dean, Counsel to the President, to John Mitchell, Attorney General of the United States and soon to be Chair of the campaign -- hiring G. Gordon Liddy, late of the Plumbers, to move from the White House into the campaign to handle "intelligence."