Based on analysis of 2 sections of legislative text.

• Creates a default rule that the Government must prove mens rea stated in a statute, and if silent, knowledge is the default for elements.
• Applies to most federal offenses punishable by imprisonment or fines of $2,500 or more, with specific statutory exceptions.
• Specified mens rea terms in a statute will apply to all elements unless Congress plainly indicates otherwise.
• Includes exceptions where Congress clearly intended no mens rea, for certain jurisdictional or venue elements, and where defaults would reduce culpability below controlling law.
• Defines key terms like "knowingly" and "willfully" for interpretive consistency.
• Protects against unconstitutional retroactive punishment and makes application prospective while permitting limited retroactivity consistent with ex post facto rules.
• Prevents later statutes from altering the new default rules unless they expressly reference and amend the provision.
• Aims to standardize liability thresholds across federal criminal law and reduce convictions based on strict liability where mens rea is absent.
• Adds a conforming table-of-sections entry to the U.S. Code.