The presidency hit a low in the 1970s, after Congress wrested authority away following Richard Nixon's Watergate abuses
Obama said he knew the standards set by each country were insufficient but that the accord was practical and meant for the long haul.
Court challenges to the phase-out of the program have now risen to the top court, whose justices will take stock of the issue during oral arguments
Mr Obama's willingness to be honest about the West's imperial past led conservative critics to accuse him of conducting an "apology tour," a meretricious dodge