In every criminal prosecution, there is a prosecutorial team and a defense team. If both teams are tax-financed, then they should receive equal amounts of tax money to pay for their operations.
In other words, the public defenders' budget should be the same as the prosecutor's budget, perhaps with a rebate-to-the-treasury requirement for each criminal defense that the public defenders don't handle. A public defender should be paid as much as a prosecutor. A public defender should have just as much money to investigate, test evidence, etc., as the prosecutor opposite.
That makes a hell of a lot of sense. I've always been uncomfortable with the idea of paying somebody for the sole purpose of putting people in jail.
Read this article