Not for lack of votes in the LDP.

[Blah Pete]

Poole is now very surprised that not a single revision has ever been made, a development he says was not anticipated at the time.

This surprising considering that one political party has been in control since the mid 50's (and a few months during the 90's).

[kamome]

There still is a strong Japanese liberal opposition to revising the constitution. This surprises me given that the right-wing are so powerful and seem to have their run of society in other contexts.

[cstaylor]

There still is a strong Japanese liberal opposition to revising the constitution. This surprises me given that the right-wing are so powerful and seem to have their run of society in other contexts.

Amending the Japanese constitution requires the people to ratify it:
Article 96:

Amendments to this Constitution shall be initiated by the Diet, through a concurring vote of two-thirds or more of all the members of each House and shall thereupon be submitted to the people for ratification, which shall require the affirmative vote of a majority of all votes cast thereon, at a special referendum or at such election as the Diet shall specify. 2) Amendments when so ratified shall immediately be promulgated by the Emperor in the name of the people, as an integral part of this Constitution.

So, unless the Diet tries to pull a coup like they did with Mori the right-wing doesn't have much say in this matter.