Many people have talked and written about the rational ignorance of voters. It is difficult for voters to become knowledgeable about the various candidates for government offices and each voter's vote is unlikely to affect the outcome, so there is no reason for voters to make the effort to become knowledgeable about the candidates.
There is another aspect of rational ignorance which is usually overlooked. Candidates have an incentive to conceal information about themselves. On noncontroversial issues, all candidates will have the same position. For example, all candidates think murderers should be punished. On controversial issues, candidates need to conceal their positions from voters who disagree with them. For the same reason, candidates have an incentive to reveal as much information as possible about their opponents. This is why political advertisements often provide information about the opponents, but provide no information about the candidate. This is also why political campaigns are so expensive. A campaign which evades issues is inherently unconvincing, so candidates must compensate by spending vast sums of money. Indirect campaigns based on symbols and feelings are much more expensive than direct campaigns which explain the candidate's positions.
Candidates' incentive to conceal information about is a consequence of voting rules. Different people have different ideas about what government policy should be. People who agree on one issue disagree on other issues. It is rare to find two people who agree on every issue. If a candidate's positions on every issue are known, then people who disagree with the candidate on one major issue might not vote for that candidate even if they agree with the candidate on every other issue. If a candidate's positions on every issue are known, then that candidate's supporters will consist of the small number of people who agree with the candidate on most issues, and no one else. If a candidate's positions on every issue are known, then that candidate will win the strong support of a small number of voters, and will lose the election to a candidate of unknown positions who has the weak support of a large number of voters.
I think that voting rules based on proportional representation with a low threshold and no requirement for a legislative majority would eliminate the incentive for candidates to conceal information about themselves, which would result in better informed voters and less expensive campaigns. I think that most voters prefer candidates with strong positions on controversial issues, but most voters do not vote for such candidates because such candidates are unlikely to win. Such candidates are likely to be elected to the legislature with proportional representation. Proportional representation eliminates the reason voters prefer candidates with weak positions. However, most systems of proportional representation require a legislative majority to elect a prime minister and pass the budget. This creates a different set of problems because minority parties can obstruct everything.
Competitive federalism solves the problem of rational voter ignorance. In competitive federalism, the most important vote is not whom to elect to government offices, but which competing government to live under. If you change which political party you vote for, this change is unlikely to change your life. But if you change which competing government you live under, this will change your life. So you have a strong incentive to be well informed before switching competing governments.
Bryan Caplan wrote a book titled The Myth of the Rational Voter. This book says that voters gain psychological benefits from stupid beliefs. A voter may vote for an idiot because voting for the idiot makes the voter feel good, and one vote does not change the outcome of the election, so voting for the idiot has no effect on how stupid government policies are. Competitive federalism solves this problem. If you choose to live under a competing government with stupid policies because it makes you feel good, you will suffer the consequences of stupid government policies.