In the letter, the Democratic party frontrunner said, "Like many members of Congress, I oppose the U.S.-Korea FTA, which I believe is badly flawed. In particular, the terms of the agreement fall well short of assuring effective, enforceable market access for American exports of manufactured goods and many agricultural products."

Obama, who relies on support from American labor unions that oppose the FTA, will have sent the letter with the November presidential election in mind. It adds another hurdle to ratification this year since even House Speaker Nancy Pelosi, who has the authority to submit the trade agreement for a congressional vote, remains negative on the FTA.

U.S. Democratic presidential hopeful Sen. Barack Obama D-Ill., speaks at the University of Charleston on March 20, 2008, in Charleston, W.Va. /AP

Saying that provisions on automobiles are very much in favor of Korea, Obama wrote, "Approval of the agreement as negotiated would give Korean exports essentially unfettered access to the U.S. market and would eliminate our best opportunity for obtaining genuinely reciprocal market access in one of the world's largest economies."

"Instead of provoking unnecessary and potentially corrosive confrontation over this agreement, your administration could make a significant contribution towards re-establishing trust with Congress and restoring bipartisan cooperation on trade by withholding the agreement,” he added.

Obama made the letter public on Saturday, even as Bush celebrated World Trade Week by saying, "I'm a strong believer that … Congress needs to pass trade agreements with Colombia, Panama and South Korea."

A Korean government official on Sunday, commenting on Obama’s effective "red light" for ratification of the FTA this year, indicated both countries would be disappointed because they had such high expectations about the trade deal.

The official described South Korea-U.S. relations by saying, "The higher the mountain is, the deeper the valley" -- hinting at disappointment in Seoul that an early honeymoon when the new conservative government took office here should so soon fade to gray.

When the new government was inaugurated, it looked as if Korea-U.S. relations were improving rapidly. President Lee Myung-bak gave top priority to the restoration of the alliance and the U.S. Congress adopted a resolution congratulating him on election. Bilateral ties reached a new high when the two leaders met at Camp David. But a deal to reopen the Korean market to U.S. beef rekindled anti-American sentiments in South Korea, and ties are unlikely to recover during Bush’s lame-duck period.

Another official said, "Obama's opposition to the FTA seems to have been politically motivated by his conflict with President Bush. If the ratification of the FTA is thwarted, this will inevitably damage Korea-U.S. relations."

But prospects are dim either way as the two countries face a series of potentially controversial bilateral issues, such as the sharing of upkeep of the U.S. Forces Korea, environmental issues arising from the relocation of U.S. military bases here, South Korea's participation in the Proliferation Security Initiative (PSI), and requests for a fresh dispatch of Korean troops to Iraq.

(englishnews@chosun.com )