Wondering why Earle didn't nail Hutchison's ass to the wall?

So was I, and google proved barely cooperative. But here's what I found:

The Case Against Kay
Last year, a grand jury was told tales about Texas' junior senator. Here's what they heard.
By Miriam Rozen

Published: Thursday, June 23, 1994

...

Then, on June 9, 1993, that suddenly changed. Four days after Hutchison's victory in the U.S. Senate runoff, McGehee, racked by guilt, went to the D.A.'s office with his stunning revelation: the newly elected U.S. senator had ordered the destruction of embarrassing state records. Burkett would later produce evidence of this: his tape, which he carted into a Travis County grand-jury room in a pizza box.

The two men told their story behind closed doors to the grand jury that would later indict Hutchison. But they never had a chance to unburden themselves in open court, before a trial jury in Fort Worth.

This February, during pretrial procedural wrangling, Judge John Onion announced that he would make no decision before testimony began on the admissibility of evidence --including material from the "pizza-box tapes" -- that Travis County District Attorney Ronnie Earle considered critical. If the trial began and Onion refused to let the jury see the physical evidence, Earle believed, it could torpedo his entire case. The D.A. made a fateful decision: he declined to move forward with the senator's prosecution. He later explained that he hoped to do so later, presumably before a more receptive judge.

Judge Onion, though, wouldn't give him that chance. Onion instead swore in a jury, then immediately ordered the panel to acquit the first U.S. senator from Texas ever to come under criminal indictment. The abrupt court-ordered acquittal left the voluminous evidence of exactly what it was that Hutchison did -- evidence that fills four walls of shelving in a locked, windowless room in the Travis County D.A.'s office -- largely hidden from public view.

...

Seems she had a little help...