President Obama appointee Beryl A. Howell cleared the way for House Democrats to further leak and try to politically damage the President when she authorized the release of grand jury materials from the Mueller investigation. This violates one of the fundamental principles of grand juries: that their proceedings must be kept secret.  As Margot Cleveland wrote in the Federalist:

Access to the grand jury materials won’t transform the House’s proceedings into a “full and fair impeachment inquiry”—it will just give the Democrats more information to selectively leak to the press. . . .

[T]here’s no need to look beyond the closed doors of the committees to conclude that the Democrats aren’t requesting the grand jury materials to avoid an injustice—but to avoid a reelection.

As the Department of Justice stated in its response today:

Once the grand jury material is turned over, DOJ said, "it cannot be recalled, and the confidentiality of the grand jury information will be lost for all time." That's especially so, the government said, if the House decides to make any of the material public, which House leaders have said they have the power to do by majority vote.

Keep in mind that this is about the Mueller investigation grand jury testimony.  This is not about the current effort to impeach President Trump over Ukraine, yet not only did Judge Howell find an exception to the grand jury secrecy requirements, she also order DOJ to turn over the documents by October 30.  As the DOJ responded:

The filings also said there is no reason for the department to produce by the end of this week grand jury information when the impeachment inquiry is scheduled to last into 2020. They also say that the Mueller investigation is “secondary” in the impeachment probe to questions about Trump’s interactions with Ukraine, lessening the need for urgency.

The release of grand jury proceedings to a partisan house on, at best, a secondary matter to the current impeachment inquiry amounts to a dangerous violation of the separation of powers and an affront to the rule of law. Grand jury materials need to be kept secret, not released for partisan political gain.