Maryland Lt. Gov. Anthony Brown and Republican Larry Hogan debate Oct. 13 at NewsChannel 8 in Arlington. President Obama will rally support for Brown on Sunday in Prince George’s County. (Melina Mara/The Washington Post)

President Obama will appear with Lt. Gov. Anthony G. Brown at a high school in Prince George’s County on Sunday in an effort to rally support for Brown’s gubernatorial campaign.

The visit is part of a multi-state push by Obama to help Democrats running for governor. He also plans to travel to his home town of Chicago this weekend to advocate for Illinois Gov. Pat Quinn, and to Michigan, Wisconsin, Pennsylvania and Maine in coming weeks.

While Obama won each of these states in 2008 and 2012, the Republican Governors Association said that Democratic candidates there are finding themselves in tighter than expected gubernatorial contests.

“GOP candidates for governor in these states are surging in the polls because they offer voters something Democrats cannot: job growth, prosperity and a focused plan to create jobs,” RGA Spokesman Jon Thompson said in a statement.

In Maryland, where registered Democrats outnumber Republicans more than 2 to 1, Brown holds a nine-point lead over Republican Larry Hogan, according to a Washington Post-Un­iversity of Maryland poll released last week.

A look at the two candidates and their views on some of the most pressing issues in the 2014 Maryland governors race.

The Post survey found that Brown is struggling to shore up support among core Democratic groups that heavily favored Obama in 2012. For example, Brown garnered support from 77 percent of African American likely voters, compared with 97 percent support from blacks for Obama in 2012, according to the network exit poll.

Six percent of black likely voters supported Hogan in the Post poll. Hogan had the support of 25 percent of white registered Democrats.

As the contest has tightened, the television airwaves have filled with anti- Hogan ads. The Democratic Governors Association has spent more than $1 million on advertisements that attack Hogan’s record on social issues. America’s Families First Action Fund, a Democratic-leaning super PAC that has been a major player in congressional races around the country, is now airing an ad that focuses on Hogan’s opposition to funding expanded pre-kindergarten and his advocacy of cutting corporate income taxes.

The Brown campaign has a new ad featuring former President Bill Clinton, who has attended two fundraisers for Brown this year that collectively raised more than $2.2 million. The footage in the commercial was shot at the first fundraiser, held in Potomac before the Democratic primary.

“I am honored to support someone that you know I believe in,” Clinton says in 30-second spot. “Anthony Brown: I think he’s the best qualified person to be governor. He’s got the right experience. He’s got the right ability and determination.”

Hogan has criticized Brown’s campaign for running attack ads that the Republican says have distorted his record on abortion, corporate taxes, pre-kindergarten education and gun control. At a news conference last month, Hogan accused Brown of peddling “absolute lies in an effort to slander and defame me.”

On Sunday, Obama will join Brown (D) and Maryland lawmakers at Dr. Henry A. Wise Jr. High School in Upper Marlboro to encourage Marylanders to cast their ballots early, the Brown campaign said. The state offers early voting Oct. 23 through Oct. 30.

Obama also stumped in Prince George’s for Gov. Martin O’Malley (D) when O’Malley ran for reelection in 2010.

The rally on Sunday is free but requires a ticket, which can be reserved on Brown’s campaign Web site or by calling 240-667-2321. Doors open at 2 p.m.

Many local lawmakers also have received tickets to hand out to their constituents.

Scott Clement contributed to this report.