I decided to look at previous Vice Presidents who have succeeded Presidents, to see how they did in primary and nominating votes.
The first one I looked at was Teddy Roosevelt, who succeeded William McKinley in 1901. Both candidates were nominated unanimously in the 1900 Republican National Convention, with the exception of TR abstaining in the Veep vote.
WMK was re-elected in 1900, and in the 1896 Republican convention, he was nominated with nearly 2/3 of the vote. TR wasn't in that race at all.
Then Calvin Coolidge, who succeeded Warren Harding in 1923. His share of the Republican convention votes declined from a little over 1/30 on the first ballot to a bit more than 1/200 on the final ballot.
Then Harry Truman, who succeeded FDR in 1945. HT was not in the Presidential race in 1932, 1936, 1940, or 1944, when FDR was.
Then LBJ, who succeeded JFK in 1963. In the 1960 Democratic convention, JFK got 53% of the vote and LBJ 27%. All the other candidates got less of the vote. So LBJ was second in line.
Then Gerald Ford, who succeeded Richard Nixon in 1974. GF succeeded RN's first Veep, Spiro Agnew, who resigned the year before after he was being investigated for having taken bribes. GF was not in the Presidential race in 1968 or 1972, when RN was.
So in summary, in Presidential nominations,
- Second place: LBJ
- Far behind: Calvin Coolidge
- Not in the running: Teddy Roosevelt, Harry Truman, Jerry Ford
So dismissing Kamala Harris as "President Select" is unjustified from the record, but then again, right-wingers are experts at inventing specious objections. Like saying that Bill Clinton was guilty of a no-no: protesting US policies while in another nation's territory, referring to his objection to the Vietnam War.