Mueller exploring Dump's power to pardon

In particular, the power to pardon people involved in the Russian collusion investigation.

• The FBI's special counsel's team is digging into the limits of President Donald Trump's pardon powers.
• Because there is little precedent for governing presidential pardon powers, the special counsel, Robert Mueller, is likely to research state-level cases with elements that could be applied to the Russia investigation.
• Experts say Mueller is taking unprecedented steps to ward off efforts by the White House to guard itself against the investigation.