Trump has stated he had to let it all go as far as he did so that they had enough evidence so that no one could say the perps were not guilty. That’s where we are today they are all guilty as sin and we have the goods on them.
Trump also has to distance himself from Barr, Sessions and others who may well have parts to play legally as attorneys or witnesses. They cannot be seen as being involved due to loyalty to Trump, but merely following the law. Esp. The Law of War. The upcoming action must be seen as not motivated or pushed by Trump personally, or people loyal to Trump. But merely following the law!