The same candidates fought to a near draw two years ago. In the latest poll, each man was favored by 40 percent of likely voters.
This year, with control of Congress in play, Maryland's easternmost district features one of the most closely watched, and expensive, House races in the country. Both sides have subjected voters to a heavy dose of negative advertising that has shaped opinions about the candidates.
Caught in the middle are independent voters like Danielle Cassano, who lives in Severna Park with her husband and two small children. She finds Harris' conservative social and fiscal views appealing and wants more Republicans in Congress, to check the Democrats' power.
She voted for Harris in 2008 and is supporting former Gov. Robert L. Ehrlich Jr.'s comeback run, in part because she's tired of seeing her taxes go up. But she's torn about backing Harris again.
She said in an interview that she's concerned about what she described as Harris' "very bad environmental record" and the "crazy things" she's heard "about him wanting to raise some taxes." The reference was to the Republican's support for a plan that would replace the federal income tax with a 23 percent consumption tax, a proposal that is a target of attacks from Kratovil and the Democrats.
Republicans had held the seat since the 1990 election, until Kratovil took it in 2008. Now, Harris is attempting to take it back.
Two years ago, Kratovil benefited from turnout for Democratic presidential nominee Barack Obama, winning by less than 3,000 votes, even though the Republican ticket of John McCain and Sarah Palin carried the district by 19 percentage points.
Deborah Gable, 53, a registered Democrat who backed Kratovil then, is among those switching to Harris.
Kratovil "basically supports the party line, and that's not where we need to be right now." He and the rest of the Democratic Party "are not listening to us" or doing enough to "put people back to work," said the Harford Community College secretary, who hasn't had a pay raise in three years.
Harris, like other Republican challengers around the country, has sought to tie the Democratic incumbent to unpopular House Speaker Nancy Pelosi. His campaign and allied conservative groups are running TV commercials to drive that message home.
A veteran state legislator from Baltimore County, Harris was an early favorite to avenge his narrow 2008 defeat. But he struggled to pull away, disappointing Republican strategists.
Heading into the final week of the campaign, he is still the favorite to win, according to some independent election analysts.
Harris has benefited from the district's Republican leanings, and from the expectation that Democratic voters who supported Obama will stay home this year.
The non-partisan Rothenberg Political Report sees the race leaning Harris' way and has factored that forecast into its prediction that Republicans will gain at least 40 seats nationally, one more than needed to take control of the House from the Democrats. The New York Times website's FiveThirtyEight computerized forecast model predicts a Harris victory and a 52-seat Republican gain.
The Sun survey results reflect the divide created by the district's geography, shaped by the Chesapeake Bay. On the western side of the Bay, Harris is favored by a significant margin.
Voters on the Eastern Shore, who consider themselves part of a unique section of Maryland, favor Kratovil, a former Queen Anne's County prosecutor, by a similarly wide margin.
Harris has tried to make inroads on the Eastern Shore, which he lost in 2008. The Johns Hopkins Hospital anesthesiologist has worked part time at hospitals in Salisbury and Easton and celebrated his primary victory in Salisbury on election night.
William Mezick, 63, of Salisbury wasn't aware of Harris' efforts to connect with Shore residents. The retired parole officer said the deluge of TV attack ads made him want to stay away from his polling place; he says he'll vote for the Republican "mainly because of his pro-life stance."
If Kratovil survives, a major reason will be his effort to separate himself from the national Democratic Party, in spite of consistent support for his re-election from national Democratic leaders.
He is also being supported again by former Republican Rep. Wayne Gilchrest, a moderate unseated by Harris in the '08 primary.
Gilchrest's backing is a big reason that Betty Gingerich, a registered Republican, will vote for Kratovil, though she doesn't agree with everything he's done in his first term.
"I really think Kratovil is independent. He goes his own way and stands up for what he thinks is right," said the retired nurse from Queen Anne's County, adding that Harris' personality "turned me off" when she met him.
Long before the tide began running against Democratic candidates across the country, Kratovil was identified as one of the most vulnerable incumbents in Congress, and both major parties have been targeting the district for many months.
That has helped make the Kratovil-Harris race among the most expensive House contests in Maryland history. More than $6.9 million had been spent by mid-October, much of it for the negative ad war.
The biggest spender, other than the candidates' campaigns, is the Democratic Congressional Campaign Committee, which dumped more than $1.1 million into anti-Harris advertising and put the Maryland contest near the top of its incumbent-defense efforts.
Harris has enjoyed active support and guidance from the National Republican Campaign Committee, which put more than $839,000 into the race.
According to both Republican and Democratic politicians, Kratovil is in a stronger position than he was six months ago.
"Andy Harris is the same guy that lost last time, so he's a retread and he hasn't changed his extreme views," said Rep. Chris Van Hollen of Maryland, who chairs the DCCC. "People are looking for someone who is interested in solving problems, not on an ideological crusade."
A significant number of voters — about 1 in 7, according to the Sun poll — remain undecided. Those voters are split fairly evenly among Democrats, Republicans and independents.
Kratovil's chances of holding his job could depend on the success or failure of Democratic efforts to rally voters who typically sit out midterm elections, by framing the choice around the fate of Obama's agenda.
Barbara Bennett of Caroline County is receptive to that argument. Her support for Kratovil is more about the president than the congressman, the 77-year-old retired office manager said.
Obama "needs a better chance," said Bennett, a registered Republican. "He's only been in office a couple of years and they're expecting miracles from him."
The poll, conducted Oct. 15 to 20, has a 4.3 percentage-point margin of possible sampling error. The Sun surveyed 520 voters in the First District, which takes in portions of Baltimore, Harford and Anne Arundel counties and the entire Eastern Shore.
Sun Poll methodology
The Baltimore Sun telephone survey of 520 likely voters in the First District was conducted Oct. 15-20. The Sun's pollster, OpinionWorks of Annapolis, used a Maryland Board of Elections database to identify registered voters with a history of voting in gubernatorial elections or who had registered to vote since the last election, and obtained survey results from those who ranked themselves seven or higher on 1-to-10 scale of their likelihood to vote. The Sun's sample was designed to approximate the racial, gender, geographic, partisan and age breakdown of the state's voting population as a whole, based on turnout patterns averaged over the last four Maryland general elections. Results were weighted to reflect a higher-than-average Republican turnout this year, and slightly lower African-American participation than in recent elections. The margin of error for the First District question is 4.3 percentage points, which means that in 95 times out of 100, the actual answer obtained by surveying every Maryland voter would be within 4.3 percentage points of the answer obtained by using the sample.