That’s because Mueller may calculate that if he tries to bring charges in the obstruction case — the part that may hit closest to Trump personally — witnesses may become less cooperative in other parts of the probe, or the president may move to shut it down altogether…

The obstruction portion of the probe could likely be completed after several key outstanding interviews, including with the president and his son, Donald Trump Jr. The president’s lawyers have been negotiating with Mueller’s team over such an encounter since late last year. But even if Trump testifies in the coming weeks, Mueller may make a strategic calculation to keep his findings on obstruction secret, according to the current and former U.S. officials, who discussed the strategy on condition of anonymity.

Any clear outcome of the obstruction inquiry could be used against Mueller: Filing charges against Trump or his family could prompt the president to take action to fire him. Publicly clearing Trump of obstruction charges — as the president’s lawyers have requested — could be used by his allies to build pressure for the broader investigation to be shut down.