Statistics regarding the frequency of obstruction of justice prosecutions are unclear. In 2004, federal agencies arrested 446 people for obstruction, representing 0.3 percent of all federal arrests. This does not include, however, people who were charged with obstruction in addition to a more serious underlying crime.
Under the Federal Sentencing Guidelines, a defendant convicted of any crime is subject to a more severe sentence if they are found to have obstructed justice by impeding the investigation or prosecution of their crimes. While a separate conviction for the crime of obstruction would require proof beyond a reasonable doubt, a finding of obstruction for sentencing purposes only needs to meet the looser standard of "a preponderance of the evidence" (unless the enhanced sentence would exceed the statutory maximum sentence for the underlying crime).
An obstruction finding adds two levels to the offender's sentence, which can result in as much as an additional 68 months of prison. In 2017, the obstruction enhancement was applied in 1,319 cases, representing 2.1 percent of all sentences issued in federal courts.
State laws regarding obstruction of justice vary widely. A 2004 survey found that 24 states and the District of Columbia had a general statute criminalizing obstruction of justice or obstruction of government functions in broad terms, similar to those found in federal law. All states have laws prohibiting some specific types of obstruction, such as witness tampering, jury tampering, or destruction of evidence.
A scandal in 1830 led to reform of the contempt law and the creation of obstruction of justice as a separate offense. Federal judge James H. Peck imprisoned a lawyer for contempt for publishing a letter criticizing one of Peck's opinions. In an effort to prevent such abuses, Congress passed a law in 1831 limiting the application of the summary contempt procedures to offenses committed in or near the court. A new section, which survives today as the Omnibus Clause, was added to punish contempts committed outside of the court, but only after indictment and trial by jury.
In 1982, in response to concerns that the obstruction law did not provide adequate protection to crime victims and other witnesses, Congress broadened the law against witness tampering and criminalized retaliation against witnesses, as part of the Victim and Witness Protection Act.
The Sarbanes–Oxley Act of 2002 strengthened the obstruction laws regarding destruction of evidence before an investigation or proceeding has begun, in response to accounting firm Arthur Andersen's widely reported shredding of documents related to the Enron scandal.
The impeachment proceedings against Richard Nixon in 1974 included charges of obstruction of justice for impeding the investigation of the Watergate burglary. Nixon's acts of obstruction, as alleged by the House Judiciary Committee, included lying to investigators and withholding evidence, influencing witnesses (including through payments of hush money), and making false statements to the public about the investigation. Nixon resigned before impeachment could be considered by the full House of Representatives, and he was preemptively pardoned by Gerald Ford before any criminal investigation could occur.
The impeachment of Bill Clinton in 1998 included allegations that Clinton obstructed justice by trying to influence the testimony of witnesses, including Monica Lewinsky, in the sexual harassment lawsuit filed against him by Paula Jones, and by encouraging Lewinsky to conceal evidence. Clinton was acquitted of all charges by the Senate.
Accounting firm Arthur Andersen was charged with obstruction of justice in 2002 for allegedly destroying and altering documents in anticipation of an investigation of the Enron scandal. The company was convicted and effectively destroyed, though the conviction was later overturned.
Conrad Black was convicted of obstruction of justice in July 2007 for removing 13 boxes containing financial records from his office in Toronto after they had been sealed by a court order, returning the boxes a few days later. Black was pardoned by Donald Trump in May 2019.