I have a question about presidential pardons?

Presidential authority to grant pardons or other clemency for violations of federal law is provided in Article II Section 2 of the Constituion. Pardon powers appear to be broad, but have also been criticized by legal experts as vague in defining reasonable limits.

As far as your question the answer may be yes, it’s concievable that a president could grant a pardon before someone is actually charged – or even investigated. The precedent for that was set in 1974 when president Ford issued a pardon to former president Nixon for “all offenses against the United States which he, Richard Nixon, has committed or may have committed or taken part in during the period from January 20, 1969 through August 9, 1974”. At that time Nixon faced no federal charges, and no offical investigation was under way. BUT, Ford’s decision was highly criticised and never subjected to an appeals test in any court. It remains only a historical example with uncertain legal value.

So could Biden (or even Trump) pardon Assange, either before or after any conviction? Maybe. But it’s highly unlikely. In blunt terms Assange is a self-serving asshole who has no friends in government, and few anywhere else.

From the Constitution of the United States, Artible 2 Section 2 Clause 1:

The President shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States; he may require the Opinion, in writing, of the principal Officer in each of the executive Departments, upon any Subject relating to the Duties of their respective Offices, and he shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment.