Obstruction of justice in the United States means an act committed with the intention to interfere improperly with the administration of law.
18 U.S.C. § 1505 makes it a felony to interfere with a pending proceeding of a department or agency of the US government. This statute also makes it felony to interfere in a Congressional investigation.
18 U.S.C. § 1503 criminalizes interference with a juror (including a member of a grand jury) or government official in a federal case.
Some ways that a defendant might obstruct justice would be by lying to a government investigator, falsifying evidence, and threatening or bribing a juror.
What about the President?
Recently, there has been concern that President Trump might have obstructed justice by interfering with one or more investigations into Russian meddling in US elections.
President Trump apparently told the former director of the Federal Bureau of Investigation, James Comey, that he “hoped” the director would cease investigating a former high level government official, Michael Flynn. Flynn was Trump’s national security advisor and had to be fired after it became clear that he had not disclosed meetings with Russian officials. President Trump also allegedly demanded loyalty from Mr. Comey. The investigation did not end and Trump fired Comey.
Opinions differ as to whether evidence to date is sufficient to allege that President Trump obstructed justice. A prominent professor, in an opinion in the New York Times. questioned whether an FBI investigation is a “pending proceeding” for purposes of 18 USC § 1505. In addition, Trump’s supporters doubt whether Trump’s statements to Comey constituted obstruction because Trump did not expressly tell Comey to not investigate Flynn. Nor did Trump expressly threaten or bribe Comey.
On the other hand, some commentators and politicians believe that Trump’s statements and actions together raise serious concerns that Trump has obstructed justice.