With less than seven months until the start of the Games, USADA chief Travis Tygart said Russia shouldn't be allowed to compete during the track-and-field events, which run for 10 days during the event.
"it's too late to ensure that those in this state supported doping program are not receiving a benefit from that programme," he
"Where we are right now. Them still denying, them still attacking the whistleblowers and the truth, with no lab, with no testing a few months before the Games, it's impossible to correct."
The Russian federation was temporarily suspended by the World Anti-Doping Agency (WADA) in November after release of a report by an independent commission detailed state-supported doping.
A task force from the International Association of Athletics Federations (IAAF) spent this week in Moscow working with Russian officials to find solutions to Russia's doping problems, and the task force's leader said the country was making efforts to reform.
This hasn't swayed Mr Tygart, who said things cannot be corrected in time for Rio.
"Even if you hold all those involved accountable, it is impossible to correct the situation to ensure those in the state-supported doping program are not going to violate the rights of the clean athletes," Tygart said.
"But when it has been demonstrated that you have run a state-supported doping program in violation of the Olympic values and spirit, you have gone against the very purpose of what the Olympics is all about."
This comes after the release on Thursday of a damaging report by a WADA independent commission that found that former and blackmailed athletes while senior officials looked the other way.
As a result of the report, Tygart said he did not believe the IAAF was in compliance with the World Anti-Doping Code.
"You can't possibility be code compliant if your sport leaders extort athletes to cover up doping that allows dirty athletes to compete in the 2012 Olympics," Mr Tygart said.
"If you can be WADA compliant with that going on, then WADA compliance means nothing. Clean athletes have no hope."
The American anti-doping leader said he wholeheartedly agreed with Thursday's WADA report that structural changes must be made by the IAAF so the type of corruption described in the report is not so easily accomplished.
The IAAF and any federation cannot just say the right things, but must actually do it, he said.
"It is not for us to decide who is in charge of the IAAF," Tygart said. "Whoever it is has to stop trying to managing the bad PR, but instead take action by proving to clean athletes that those involved with this corruption will be held accountable.
"Change or be changed," he said. "Athletes will revolt, and they should, if their sport leaders don't use this moment to ensure accountability for all those involved to ensure it will never happen again."
