As the Senate prepares to tackle the most sweeping immigration reforms in years, a top Democrat vowed Wednesday to do everything in his power, including filibuster, to thwart Majority Leader Bill Frist's proposed overhaul.

Minority Leader Harry Reid, D-Nev., said he would "use every procedural means at my disposal" to prevent Frist from bypassing the Judiciary Committee. Frist, R-Tenn., has made clear the Senate will take up his proposal next week if the 18-member committee fails to complete a broader bill.

"If Leader Frist brings a bill to the floor that does not have the approval of the Judiciary Committee, it will not get out of the Senate," Reid told reporters at the San Ysidro border crossing, a few steps from Tijuana, Mexico.

Bob Stevenson, a spokesman for Frist, did not immediately respond to a call Wednesday evening.

Sen. John Cornyn, R-Texas, who authored the Comprehensive Enforcement and Immigration Reform Act of 2005 with Sen. Jon Kyl, R-Ariz., said he was dismayed by Reid's threat.

"It's discouraging that before the debate has even begun in the full Senate, the Democrat leadership is threatening to filibuster any legislation that doesn't include amnesty. This is not the way to improve our national security and keep Americans safe," Cornyn said in a statement.

Reid said the overhaul must include heightened border enforcement, a "guest worker" program and a "path to citizenship" for the estimated 11 million people in the United States illegally. He called legislation by Sens. Edward Kennedy, D-Mass., and John McCain, R-Ariz., a "good place to start."

President Bush, in a State of the Union address two years ago, urged Congress to create a guest worker program under which participants could gain legal status for a specific time and then be required to return home. It would not provide an automatic path to citizenship.

Frist unveiled a bill last week that sidesteps the question of temporary work permits. It would tighten borders, punish employers who hire illegal immigrants and provide more visas.