One of the more common questions I get is whether you can an evidentiary hearing. The question usually comes up in cases where the evidence weak. Sometimes clients simply want a hearing where the state has to show all their evidence. Unfortunately, the answer in both situations is no.
Many people believe that a judge can dismiss a case if he or she believes there is insufficient evidence. They do have that authority, but not until after the trial starts. Then they can grant a directed verdict after the State rests. Before the trial starts though, a judge cannot force a prosecutor to dismiss a case. That's a hard concept for some people to accept.
A judge's role is to basically referee the trial, and the proceedings leading up to trial. If there is evidence that needs to be suppressed the judge will make that decision. The judge can also make decisions on whether certain evidence can be disclosed, or tested. The judge will also make pre-trial rulings that control how the case will be presented. At no time however is the judge presented with all the evidence the State has.
A judge in Texas also cannot force the State to show all their evidence - at least not now. (Starting on January 1, 2014 the State will have to provide offense reports to a defendant's lawyer) They can order the State to allow the defense and their experts to look at evidence, but the actual evidence remains with the State.
There are a lot of differences between criminal and civil trials. Even though life and liberty are stake discovery is more limited, as is the judge's control over the case. That's something I've never understood - and after more than 30 years I'm sure never will.