World Anti-Doping Agency boss Dick Pound has accused the US administration of showing no interest in the fight against drugs in sport.
Pound has lost patience with the US
And the WADA president said the lack of support from George Bush's government could lead to sanctions against the US team at next summer's Athens Olympics.
He also warned that it could threaten New York's bid for the 2012 Games.
"Our sense is they're not the slightest bit interested in this issue," said Pound.
"There's just a complete vacuum and void there as far as we're concerned."
Pound said the United States, Italy and Ukraine were among the countries yet to pay their annual dues to WADA, which is jointly funded by the Olympic movement and national governments.
WADA, which was created in 1999 to spearhead global drug-testing efforts, has collected less than two-thirds of its funding for 2003 - about $13m of its $20m budget.
The contributions were due by the beginning of this year.
Pound said the US government had promised to pay $1m, but that WADA had been informed by a junior White House drug office employee that the figure would be only $800,000.
"We've had great support from the Congressional side... but vis a vis the White House we are just striking out and are very disappointed in the lack of leadership being demonstrated," said Pound.
The Canadian lawyer said the White House position was "all the more inexplicable" given the recent doping developments in the USA.
He cited positive tests for the designer steroid THG and stimulant modafinil, as well as drug controversies involving USA Track & Field, the US Olympic Committee, Major League Baseball and the NFL.
Jennifer de Vallance, spokeswoman for the White House Office of National Drug Control Policy, called Pound's comments "disingenuous and unproductive".
"We work with his staff on a regular and close basis," she said. "We remain steadfastly committed to WADA's mission."
De Vallance said the US contribution was always set at $US800,000 and not $1m.
She added that Congress was expected to pass the federal budget in the next few days, clearing the way for payment of the WADA dues.
WADA sanctions against governments which do not pay could include stripping them
of their seats on the WADA board and executive committee.
The IOC could also refuse accreditation to government officials for the Athens Olympics and prohibit use of the national flag at opening, closing and medal ceremonies.
Pound said International Olympic Committee president Jacques Rogge had also suggested that countries which did not pay contributions or enact the WADA code could be banned from bidding for the Olympics.
That could apply to New York's 2012 bid and also affect Rio de Janeiro, because Brazil had never paid any dues to WADA.