Butcher intended to seek the Conservative nomination again for the 2006 election, but withdrew shortly before the vote.
Mr. Long said Bush campaign officials had asked him recently whether the "door was closed" to the Conservative nomination.
In both elections, the Conservative nomination could be the balance of power.
He supported the merger and eventually defeated two other candidates to win the Conservative nomination.
In 1968, 1970, and 1972, he also got the Conservative nomination, but this support ended after his abortive run for mayor in 1973.
He entered the Democratic primary, and also sought the Conservative nomination.
He was the first candidate to declare for the Conservative nomination in the buildup to the 2006 election, focusing on health and environmental issues.
He faced a primary challenge for the Conservative nomination.
He attempted to run for the Conservative nomination for the next federal election but was refused.
He contested the Conservative nomination for the London mayoral elections in 2000, 2004, and 2008.