Concerning all of the legal issues related to Hillary Clinton they tried not to make a case.
Against Trump they are being exceedingly aggressive.
National Review
The Trump Collusion Case Is Not Getting the Clinton Emails Treatment
“If the Justice Department is hell-bent on making a case, it plays an intimidating game of hardball. In July 2016, the Obama administration announced its decision not to prosecute Hillary Clinton for felony mishandling of classified information and destruction of government files. In the aftermath, I observed that there is a very aggressive way that the Justice Department and the FBI go about their business when they are trying to make a case — one profoundly different from the way they went about the Clinton emails investigation. There, they tried not to make the case.”
“Mueller succeeded in convincing a federal judge to force an attorney for Manafort and Gates to provide grand-jury testimony against them.”
“Interestingly, the jurist who rendered the 37-page memorandum opinion is Beryl A. Howell, who served for years as a senior Judiciary Committee adviser to the fiercely partisan Democratic Senator Pat Leahy (of Vermont) before being appointed to the bench by President Obama. Howell is now the district court’s chief judge. Why do I think that, in choosing to set up shop in Washington, Mueller and his team noted the district court’s local rule that vests the chief judge with responsibility to “hear and determine all matters relating to proceedings before the grand jury”? (See here, Rule 57.14 at p. 168.)”
“Compare that with the Justice Department’s treatment of the lawyers representing Mrs. Clinton and her accomplices. Actually, I shouldn’t really put it that way because . . . Mrs. Clinton’s lawyers were her accomplices.”