By Doug Palmer

WASHINGTON (Reuters) - U.S. union groups, frustrated by what they describe as a decade of broken promises by China since the Asian economic giant joined the World Trade Organization, are pressing Congress to take a tougher approach with Russia, which is poised to enter the WTO.

The plea came as U.S. business groups push Congress to prepare for Russia's entry into the WTO on August 22 by lifting a Cold War-era human rights provision known as the Jackson-Vanik amendment to establish "permanent normal trade relations" (PNTR) between the two countries.

"We have had more than a decade of experience with China and their promises made, promises broken," the United Steelworkers and the Communication Workers of America said in a letter sent on Monday to every member of Congress.

"Farmers, workers and businesses should at least be able to have faith that if their government negotiates an agreement and tells them of its benefits, that those benefits will be available to them," the unions said.

The Jackson-Vanik measure made favorable U.S. tariff rates conditional on the rights of Jews in the former Soviet Union to emigrate freely. Russia has been judged in compliance with the emigration provisions since 1994. But the Jackson-Vanik provision remains on the books, at odds with WTO rules requiring members to unconditionally treat imports from all other members the same.

If lawmakers fail to act before Congress adjourns for its August recess, Russia could at least temporarily deny U.S. exporters some concessions it made to join the WTO.

The House of Representatives Ways and Means Committee is expected on Thursday to approve PNTR legislation based on a bill that sailed through the Senate Finance Committee last week on a 24-0 vote. But it is unclear if the full Congress will act before August.

The Finance Committee bill directs the U.S. Trade Representative's office (USTR) to report within six months on actions it has taken to ensure Russia is fulfilling its WTO commitments, and requires annual reports thereafter on USTR enforcement efforts and Russia's compliance with its obligations.

The union groups, in their letter to Congress, said that approach was not tough enough, and they endorsed another bill offered by Senator Sherrod Brown and Representatives Michael Michaud and Rosa DeLauro, all Democrats. Continued...