Even as the International Monetary Fund announced a $7.8 billion loan today to helpMexicoout of its currency crisis, President Clinton's once-popular peso rescue plan was hard aground in Congress. A key Democratic senator, Ernest Hollings of South Carolina, this morning attacked Clinton's $40 billon loan guarantee proposal as a "billionaires' bailout," saying Mexico is unlikely to pay it back. "Let's cut out this nonsense of trying to hoodwink the American people," Hollings told the Senate Foreign Affairs Committee, where Chairman Jesse Helms (R-N.C.) ignored GOP leaders more sympathetic to the plan by giving its opponents a daylong public forum to gripe. Treasury Secretary Robert Rubin touted the IMF loan -- largest in the organization's 51-year history -- as the international community's vote of confidence on Mexico's ability to recover. But in Congress, says TIME's Tumulty, "right now it's just a big mess. The president's version cannot pass, but they know they have to pass something."