Just curious, since a DUI in Canada results in a felony, would the US allow the felon to enter the US?
If any individual happens to be a citizen returning to their own country, the answer would be YES.....
United States and Canada citizens (or one with legal status) returning to their home countries will not be denied entry, as criminal records do not pertain to the rule....
If this question pertains to a citizen that is not a US citizen entering the US, more likely they will be denied entry by US officials but the determining factor for granting entry is what is the purpose of visiting the US....
If it is someone that wants to vacation in an RV, probably not and most likely they will be sent back to Canada....recently there have been a small handful of Canadians without any criminal record that were denied into the US....
If it is someone that is a big performer, world class athlete, or some other big money work visa individual....maybe they will be granted permission as they will pay big bucks for a similar US waiver version at the discretion of a US Customs or immigration officer to seek a temporary permit....depends on one's status and purpose.