A legislator is faced with the unpleasant necessity of standing for election periodically.
In the political debates that accompany an election campaign, a candidate wishes to claim credit for all the good things that have been done by the legislature during his incumbency, while at the same time denying responsibility for all the bad things that have been done.
Of course not all segments of the electorate regard the same legislative acts as good or bad.
So the byword for the politiican is flexibility. He or she must have "wiggle room" to maneuver in addressing the concerns of electorate.
The technique which has emerged has been highly complex pieces of legislation, with many chapters, sections, and paragraphs, full of obscure language, and duly revised and amended with riders, earmarks, substitutions, strikeouts, and memoranda so that even a first reading takes days.
A legislator who votes in favor of a complex bill can single out sections that are important and valuable to whomever he or she is addressing; while one who voted against can point to parts of the bill that are anathema to the audience. Thus every political decision can always be justified to every audience.
Complex bills are useful for another purpose - adding provisions that are requested by special interests.
The remedy for these evils is to require bills that are short, simple, and unamendable, requiring an up-or-down vote. This practice would soon produce a legislative record that would undeniably identify the positions taken by each member, and provide clear information to be aired at the next election.
The system of complex bills that is so common today merely serves to protect the interests of the politicians. The public needs procedures that enable them to require legislators to act in the public interest.