As debate in Congress raged this year over the president’s plan for Iraq, U.S. Reps. Charlie Dent and Jim Gerlach frequently turned to one another for each other’s take. The two Republicans, after all, know each other well.

Dent, of the 15th District, and Gerlach, of the 6th, in their nearly 18 years as political allies, have established as close a bond as any two lawmakers in the state delegation, forged by nearly identical routes to Congress, neighboring districts and — after last year’s election drubbing for the GOP — increasing isolation as Republicans amid a sea of southeastern Pennsylvania Democrats.

‘‘It is not surprising that you find two members who have a lot in common running in an increasing field of Democrats,’‘ said pollster Michael Young of Harrisburg. ‘‘They both seem to me to exhibit traits of as close as what it means to be a Republican in eastern Pennsylvania today.’‘ Young was referring to the lawmakers’ more liberal positions on social issues and willingness to cross party lines.

Seldom does the pair disagree on significant votes. They’ve sided together on 95 percent of the more than 1,100 votes this year, according to the washingtonpost.com voting database. On environmental issues, Gerlach’s voting record is a tad greener. On issues involving reproductive rights, it’s a shade more conservative. But the differences in their voting records are minor. Dent has sided with the Republican Party on votes 84 percent of the time this year; Gerlach 83 percent of the time.