RealClearPolitics has an excellent review of the facts surrounding Ronnie Earle's indictment of Tom DeLay. In a nutshell, Earle has done a number of things that are no-nos in the legal community.
He took his facts to three different grand juries, having been rejected by one of them. He found a grand jury that would rubber stamp his effort to indict DeLay on specious charges. He didn't like what he saw with one grand jury, so he moved to another. And the Constitutionally confused John Birch Society members can hold their fire. This is not double jeopardy. He hadn't been charged yet, so therefore, there was no jeopardy to begin with. While certainly not illegal, and probably not violative of any rules governing professional conduct (which is not to say that it is not morally unethical), he did what we call "forum shopping." It indicates the weakness of Earle's case, and his deperation to tag his political opponent.
Also, per the RealClearPolitics piece, Earle has procured an indictement against DeLay for acts that, as alleged, were not illegal when they were alleged to have been done. Put another way, DeLay did nothing illegal. If he committed them today, he would certainly be in trouble. But DeLay, even though he is a Republican, still has some Constitutional rights, chief among them, those guaranteed by the 5th and 14th Amendments, guaranteeing him substantive and procedural due process rights, which protects one from ex post facto prosecutions. Laws cannot be made, nor can existing laws be twisted to allow for prosecutions of behavior that predated their enactment. We can't make laws to stick people after the fact. It's why Charles Manson did not go to the California gas chamber. Sentenced to death in 1971, the Supreme Court illegalized the death penalty the next year, granting Manson a life sentence. Therafter, in 1976 when the Court changed its mind on the death penalty, impliedly reserving it for murders only, Manson, a prime candidate, still skipped by, as his condition could not be made worse by the law. But Earle, being only too eager to ignore Mr. DeLay's rights has brought up the final issue which is indeed a problem for him.
Malicious prosecution or more generally, prosecutorial misconduct, is a simple term that means that a prosecutor may not prosecute someone whom they reasonably believe did not commit the charged offenses. Prosecutors who use their power to intimidate those who have not committed crimes can be disciplined by the Bar of their state, and depending upon the degree of abuse, deprived of their licenses to practice law.
To be fair, it is one thing for a prosecutor to know that there are holes in his/her case. It is quite another for the prosecutor to target someone whom they reasonably believe did not commit an illegal act, and it is even worse if done to further an objective other than enforcement of the law.
And while I am no fan of some of Tom DeLay's fund raising tactics, the Republicans owe him a debt of gratitude. DeLay has raised funds to keep Republicans in office and winning elections, and thereby has defended the Republican majority. If he committed proscribed acts--after laws making them illegal were passed, of course--then he deserves the penalty he gets.
But if this is what it seems, with Earle prosecuting a man for something that was not criminal when done, on top of his history of prosecuting other political opponents, it may be in the interests of justice to have Ronnie Earle reported to the Texas State Bar and deprived of his right to practice law, or at the very least, removed from his office as a prosecutor.