A U.S. Entry Waiver (Advanced Permission for Admissibility) is a document that allows people who have been convicted of a criminal offence to legally enter the U.S. You may have often passed through the U.S. Immigration and Naturalization Service (INS) after answering a few standard questions about your citizenship and the purpose of your trip. You have been lucky. It is becoming more common for U.S. immigration officers to ask for identification for the purpose of conducting a criminal record search.
If you must travel to the U.S. before your Canadian criminal record is pardoned or destroyed, you will need to apply for a U.S. Entry Waiver to legally enter. Essentially, you will be admitting and giving details about your criminal record to the U.S. federal government. If you have already been turned away at the border a U.S. Entry Waiver is essential for re-entry.
You will be required to submit fingerprints for certification to the RCMP. In addition to the basic application, there are supporting documents that Pardons Canada can help you acquire.
Pardons Canada can help you determine the required next step, taking into account the date of your offence, the nature of your offence, current U.S. sentiment and practices, and your personal situation.