03/28/2008 02:48 am ET Updated May 25, 2011

Latest Poll: McCain Beats Clinton, Obama Beats McCain

The latest national tracking poll - released today, President's Day - shows John McCain beating Hillary Clinton, 49%-42%. The Rasmussen Reports poll also shows Barack Obama beating McCain 46% to 43%.

Clinton has slipped over the last week - on Feb. 11, Rasmussen had McCain ahead of Clinton 45%-43%, which was within the margin of error.

The new poll also found Obama with the highest "favorable" ratings among likely voters. Obama is viewed favorably by 54%; McCain by 51%, and Clinton by only 45%.

The biggest effect of poll numbers like these is probably on the Democrats' superdelegates. Elected officials and members of the party establishment, they tend to be cautious and careful, eager to avoid alienating likely winners, and focused more on winning elections than on policy or personality differences between the candidates. "The Democrats created superdelegates after the 1980 campaign to help ensure their nominee was mainstream and electable," CBS news explained on Saturday. "Electability" provides a firm basis for superdelgates to choose Obama -- if poll results like this hold up.

Of course polls measure voter sentiment today. The purpose of campaigns is to win more voters by November, and some campaigns succeed. Clinton's still could.

Rasmussen also reported that, on President's Day, both Lincoln and Washington have higher favorability ratings than any current candidate: Lincoln is viewed favorably by 84% of American adults, Washington by 79%.

The Rassmussen daily tracking poll is conducted with nightly telephone surveys and averaged over the previous four days. The sample consists of 1,600 likely voters, and the margin of error is 3 percentage points.