Eric Garcetti (4th L), Mayor of Los Angeles, attends a press conference after the presentation of the Los Angeles 2024 Candidate City Briefing for International Olympic Committee (IOC) members at the SwissTech Convention Centre, in Lausanne, Switzerland, July 11, 2017. [Photo/Xinhua]

The dual award can give the IOC a decade of stability with two world-class cities touting financially secure bids. LA plans to use only existing venues with zero risk of white elephants. This follows years of overspending by Olympic hosts and a series of political defeats that have sunk the campaigns of potential candidates.

It also avoids inflicting a third recent defeat on Paris — which lost with bids for the 2008 and 2012 Olympics — and the United States. New York and Chicago both lost heavily for 2012 and 2016, respectively.

Those losses deepened a rift between the US Olympic Committee and the Swiss-based IOC that LA 2024 and a new team of American officials have worked hard to heal.

Paris also failed with a 1992 bid and pinned its hopes on hosting in 2024, exactly 100 years after its previous Summer Games.

Garcetti said the Olympic movement "can't afford to lose the United States."The IOC's most valuable TV rights deal is with NBC and several of its top-tier sponsors are American.

Still, a 2028 Olympics in Southern California could be the first American-hosted games since 1996 in Atlanta.

Bach has said the idea of a double award was presented to him at a lunch last year by friends whom he declined to identify in a recent interview with French sports daily L'Equipe.

The LA bid team declined to comment Tuesday whether the suggestion came from its supporters, as some believe.

"He (Bach) has good friends who gave him good advice," LA bid chairman Casey Wasserman said.