The latest Rasmussen Reports national telephone poll finds Illinois Senator Barack Obama (D) with an eight point lead over Arizona Senator John McCain (R). It’s Obama 46% McCain 38%.

Obama’s total is unchanged from a month ago, but McCain has lost four percentage points since May. This is the third straight monthly poll in which Obama has enjoyed an advantage over McCain. For the two months before that, they were tied.

Obama is now viewed favorably by 50% of all voters and unfavorably by 44%. Among Democrats, 70% have a favorable opinion. The newcomer to the national scene consistently polls in second place among those seeking the Democratic Presidential nomination.

In other general election match-ups, Obama trails former New York City Mayor Rudy Giuliani by double digits, leads former Tennessee Senator Fred Thompson by three points, and leads former Massachusetts Governor Mitt Romney by twelve.

McCain’s popularity has been falling throughout the campaign season. Currently, he is viewed favorably by 48% of American voters and unfavorably by 45%. Last December, McCain had been viewed favorably by 59% of voters. As recently as two months ago, 55% had a positive assessment of the Senator from Arizona.

McCain is now viewed favorably by just over half (55%) of those in his own party. Only 10% of GOP voters have a Very Favorable opinion of him. Forty-percent (40%) have an unfavorable opinion.

When the season began, McCain was perceived as the dominant frontrunner for the Republican Presidential nomination. As the year has unfolded, voters have come to see McCain as more and more conservative. Despite this shift to the right, he has been losing ground in a nominating process dominated by conservatives. His support has fallen to 11% in our latest polling of that race. That’s just half the support he enjoyed in January. Rasmussen Reports released a special look at what has happened to the McCain campaign.

In other match-ups, Senator McCain leads New York Senator Hillary Clinton but trails former North Carolina Senator John Edwards.

Rasmussen Reports continuously updates favorability ratings and general election match-ups for all Democratic and Republican candidates. Also available are ratings for Members of Congress, Other Political Figures, and Journalists.