WASHINGTON (CNN) -- Americans oppose President Bush's plan to send additional troops to Iraq by a two-to-one margin, according to a CNN/Opinion Research Corporation poll released Friday.

Two-thirds of Americans also say Bush has no clear plan for Iraq.

While his numbers have inched up slightly on that question since the previous poll a week earlier, Bush's address to the nation Wednesday night seems to have made no difference in his effort to win support for the plan.

Nearly half those who saw the speech say their minds were not changed, while the rest are evenly split over whether they'd be more or less likely to support his policies.

This is the first poll gauging Americans' positions on the strategy following Bush's address. The survey of 1,093 adult Americans was conducted Thursday.

Asked their positions on sending more troops to Iraq, 66 percent said they oppose the move, while 32 percent said they favor it.

The sampling error on this, and all the questions in the poll, is plus or minus three percentage points.