Incumbent Democrat Martin O’Malley and Republican challenger Bob Ehrlich remain essentially tied for the third month in a row in the race for governor of Maryland.

The latest Rasmussen Reports telephone survey of Likely Voters in the state finds O’Malley with 45 percent support and Ehrlich earning 44 percent of the vote. Three percent (3 percent) prefer some other candidate in the race, and eight percent (8 percent) are undecided.

A month ago, Ehrlich squeaked ahead 47 percent to 46 percent. But the rematch of the 2006 governor’s race has been tight from the start. In February, O’Malley led 49 percent to 43 percent, but by April it was a closer 47 percent to 44 percent. By June, the two were tied with 45 percent of the vote each.

When leaners are included in the new results, O’Malley and Ehrlich are tied at 47 percent apiece.

This is the first Rasmussen Reports Election 2010 survey of the Maryland governor’s race to include leaners. Leaners are those who initially indicate no preference for either of the candidates but answer a follow-up question and say they are leaning towards a particular candidate.

Early in any campaign, the numbers without leaners are generally more significant. Later in a campaign, the numbers with leaners matter more. After Labor Day, Rasmussen Reports will report the numbers with leaners as the primary indicators of the campaign.

This race remains a Toss-Up in the Rasmussen Reports Gubernatorial Scorecard.

Seventy-eight percent (78 percent) of O’Malley’s voters are already certain how they will vote in November, and 72 percent of Ehrlich’s voters say the same.

The statewide survey of 750 Likely Voters in Maryland was conducted on August 17, 2010 by Rasmussen Reports. The margin of sampling error is +/- 4 percentage points with a 95 percent level of confidence.

In the 2006 election, O’Malley, then mayor of Baltimore, defeated Ehrlich, the first GOP governor in the state since the 1960s, by a 53 percent to 46 percent margin.

Ninety percent (90 percent) of GOP voters support Ehrlich, while O’Malley has the backing of 70 percent of Democrats. The Republican holds a modest lead among voters not affiliated with either major party.

Fifty-five percent (55 percent) of all Maryland voters regard O’Malley as a political liberal, while 25 percent see him as a moderate. Seventy-six percent (76 percent) identify Ehrlich as a conservative.

Yet despite these ideological differences, 55 percent say O’Malley’s views are in the mainstream, and 51 percent say the same of Ehrlich’s.

Twenty-seven percent (27 percent) regard the Democrat’s views as extreme, while 30 percent think that of Ehrlich’s views.

Fifty-four percent (54 percent) approve of the job O’Malley is doing as governor, up four points from a month ago, while 45 percent disapprove.

Twenty-five percent (25 percent) of Maryland voters have a Very Favorable opinion of O’Malley. Twenty-one percent (21 percent) view him Very Unfavorably.

Ehrlich is viewed Very Favorably by 24 percent and Very Unfavorably by 20 percent.

Just eight percent (8 percent) of voters in the state rate the economy as good or excellent. Fifty-five percent (55 percent) describe it as poor.

Thirty-one percent (31 percent) say the economy is getting better, but 41 percent believe it is getting worse.

Fifty-six percent (56 percent) of Maryland voters approve of the job President Obama is doing. Forty-three percent (43 percent) disapprove.

This is a better job approval rating than Obama earns nationally in the Rasmussen Reports daily Presidential Tracking Poll.