Washington ? A new organization created to defeat President Bush’s plans for Social Security intends to open a television ad campaign this week depicting the proposal as the tip of an iceberg that will cut benefits and raise the national debt.

Erik Smith, a spokesman for ProtectYourCheck.org, said the group would spend nearly $1 million to show the commercial on cable stations nationally in the next three weeks. Other ads will follow on broadcast stations, he said, aimed at individual lawmakers of both parties.

The White House, Republican Party and outside groups are working to build support for Bush’s Social Security proposal. On the other side, the Democratic Party, former aides to John Kerry and others who worked in outside organizations to elect him are now trying to torpedo the top domestic initiative of Bush’s second term.

The ad will air as Congress returns from a two-week break and the administration moves into the second half of an intensive 60-day campaign to raise public support for Bush’s call for Social Security legislation.

Brian Jones, a spokesman for the Republican party, called the ad part of a “a disingenuous scare campaign. The Democrats false attacks can’t mask the fact that the vast majority of Americans understand Social Security faces problems that need to be addressed now,” he added.