Governor Pataki couldn’t have done the Republican Party in New York a worse disservice than moving to pre-empt a lively primary to name a candidate to challenge Senator Clinton next year. We have nothing against Jeanine Pirro but Edward Cox struck us as better on the issues and well suited to the kind of ideological sorting out for which primary elections are made to order. We were sorry to see him drop out, particularly because such a sorting out is precisely what the Republican Party needs in New York. A contested primary would have been a method for involving Republicans at the grass roots in the idea that Mrs. Clinton is not invulnerable.

History teaches, moreover, that even losing races can have a big impact. In 1964, President Johnson seemed like just the type of entrenched incumbent that Senator Clinton is now, although Mrs. Clinton generates a much more negative reaction among her opponents than Johnson did and this could make her more vulnerable. In the primary, Republicans had a choice between a staunch conservative, Barry Goldwater, and a moderate – the governor of Pennsylvania, William Scranton – who had been recruited by some members of the party especially to counterbalance Goldwater. Republicans in 1964 went for Goldwater, and went down to defeat by a landslide.

The campaign, however, was an engine for growth and renewal nonetheless, helping to wrest the party away from the northern moderates and launching the careers of conservatives like a certain actor by the name of Ronald Reagan. Ms. Pirro could yet prove a formidable opponent, her rocky start and meager fundraising notwithstanding. But all primaries, and especially this one, are only ever partly about the race at hand. They are also opportunities to build the party, both by providing a forum for new ideas and also by giving experienced and up-and-coming politicians alike the chance to test their mettle and refine their campaign strategies.

It remains to be seen how helpful the governor’s endorsement will be to Ms. Pirro in the months ahead. And the other two Republicans still in the race, John Spencer and William Brenner, could yet give Republicans “a choice, not an echo” – to quote a famous phrase to emerge from Goldwater’s campaign. But by trying to forestall a primary, the governor has disregarded his party. Which is a bad omen for a politician who has been out testing the waters in respect of his own possible run for the presidency.