Rep. Christopher Shays (Conn.) is used to running into a headwind.

For years, the moderate Republican has represented a suburban district that routinely votes Democratic in presidential elections.

But according to a new poll conducted exclusively for Roll Call, the Nutmeg State’s 4th district is trending more Democratic than ever before — and Shays might pay the price on Election Day.

In the poll, conducted by SurveyUSA on Monday and Tuesday, Shays trailed his Democratic challenger, former investment banker Jim Himes, 48 percent to 45 percent.

But Shays was running far ahead of Sen. John McCain (Ariz.), the Republican presidential nominee. In the 4th district, Sen. Barack Obama (D-Ill.) led McCain 59 percent to 37 percent. And it is that Democratic surge that could prove fatal to Shays.

The poll of 602 likely voters had a margin of error of 4 points.

Shays, one of just eight Republicans representing House districts that Sen. John Kerry (D-Mass.) won in the 2004 White House election, is no stranger to tough races in difficult political environments. But he has always managed to swim against the tide.

He beat Westport First Selectwoman Diane Farrell (D) by 3 points in 2006, despite it being a terrible year for Republicans nationwide. In 2004, he beat Farrell by 4 points, even as Kerry was winning the district by 6 points. In 2000, Shays took 58 percent of the vote as Al Gore (D) won the district by 10 points in the presidential race.

But Obama’s 22-point lead over McCain in the district is unprecedented, and if it holds, could validate the Democrats’ claim that the demographics of the district are changing sufficiently to put Himes over the top.

Obama not only took 88 percent of the Democratic vote in the Roll Call poll, but he led McCain among independents 53 percent to 39 percent and even racked up one-quarter of the Republican vote. While the district is generally affluent, it has some urban pockets, and Obama presumably ran well there, taking 77 percent of the black vote and 71 percent of the Latino vote.

Democratic strategists have suggested that Himes, because of his charitable work in urban centers such as Bridgeport, is uniquely equipped to benefit from a high turnout of minority voters who are attracted to Obama’s candidacy.

During his 11 terms in Congress, Shays has thrived by emphasizing his political independence, and it appears to be moderate and independent voters who are keeping him close to Himes. In the Roll Call poll, Shays led among independent voters 46 percent to 42 percent. Self-described moderates broke in Himes’ direction 48 percent to 45 percent — an exact match of the districtwide totals. Obama, by contrast, had a 26-point lead over McCain among self- described moderates.

In another sign of how toxic the political environment is for Republicans — and the challenges Shays faces — President Bush’s job-approval rating in the 4th district, where his father grew up, was just 20 percent. Asked which party is best equipped to manage the nation’s faltering economy, voters chose Democrats by a 20-point margin.

Congress’ approval rating was a dismal 13 percent, but Shays’ overall favorability ratings were fairly strong. Forty-three percent of the survey’s respondents said they had a favorable view of the Congressman, while 32 percent said they had an unfavorable view.

Himes’ favorable-to-unfavorable ratings were 39 percent to 22 percent. Himes was clearly less well-known than the incumbent: 40 percent of those surveyed said they were neutral on the challenger or had no opinion. Just 26 percent said they were neutral or had no opinion on Shays.

In a district that is covered primarily by the uber-expensive New York City media market, the race is expected to be one of the costliest in the country. Although neither Shays nor Himes had submitted their third-quarter fundraising reports to the Federal Election Commission by Roll Call’s press time Wednesday evening, Shays had almost $1.7 million on hand on June 30, and Himes had more than $1.2 million in his campaign account on July 23. Additionally, the Democratic Congressional Campaign Committee had spent $798,000 on the race through Tuesday, according to independent expenditure reports.

Shays and Farrell spent a combined $6.7 million on their race in 2006, and both parties’ campaign committees also played heavily in the district.