Editor’s note: Every day in this space during the Democratic and Republican conventions, Roll Call will publish poll results from a competitive Congressional district.

Fresh off her come-from-behind Republican primary victory over former Rep. Jim Ryun, Kansas state Treasurer Lynn Jenkins is within striking distance of freshman Rep. Nancy Boyda (D-Kan.), according to a new poll conducted exclusively for Roll Call.

But Boyda, who upset Ryun in 2006 despite the heavy Republican lean of the eastern Kansas 2nd district, was at the critical 50 percent mark in a head-to-head matchup with Jenkins. And Kansas voters viewed Boyda fairly favorably despite their strikingly poor opinion of Congress and the fact that they preferred Sen. John McCain (R-Ariz.) to Sen. Barack Obama (D-Ill.) by 13 points in the presidential race.

Asked whom they would vote for in November, 50 percent of poll respondents said Boyda and 43 percent said Jenkins. The poll of 620 likely voters, conducted Aug. 19-21 for Roll Call by the automated polling firm SurveyUSA, had a 4-point margin of error.

Boyda is considered one of the most politically vulnerable House Democrats this election cycle. She upset Ryun by winning 51 percent to his 47 percent in 2006 despite losing to him by 15 points two years earlier.

The 2nd district, which includes Topeka, is a Republican stronghold at the presidential level, giving President Bush 59 percent of the vote to 39 percent for Sen. John Kerry (D-Mass.) in 2004. That trend appears likely to hold this fall, the Roll Call poll found, as 51 percent said they planned to vote for McCain in the White House election, compared with just 38 percent who planned to vote for Obama. Seven percent said they planned to vote for someone else, and 4 percent were unsure.

Obama, whose mother and grandparents came from Kansas, hopes to do better in the Plains and Mountain states than Democratic presidential contenders traditionally do.

Bush had a 36 percent job approval rating in the 2nd district, according to the poll, which is marginally stronger than it is at the national level. But the approval rating for Congress was an alarmingly low 10 percent. A whopping 79 percent said they disapproved of the job Congress is doing.

Still, Boyda may be benefiting from the general nationwide trend where voters hate Congress but like their own Member. Forty-six percent said they had a favorable opinion of Boyda, while 32 percent viewed her unfavorably. Eighteen percent said they were neutral, while 4 percent had no opinion.

Jenkins, a two-term statewide elected official who just came off a contentious primary with Ryun, appeared to be far less well-known. A third of the district voters had a favorable opinion of her, while 23 percent were unfavorable. Another third were neutral, while 11 percent had no opinion.

Jenkins trailed Ryun in publicly released polls before the Aug. 5 GOP primary but went on to win by 2 points. She is considered more moderate than the former Congressman, which should help her in the November contest with Boyda.

While high gas prices and energy issues are the topics occupying many Members of Congress, the poll found that 37 percent of 2nd district voters are most concerned about the overall economy, compared with just 11 percent who answered that gasoline prices are their top concern.

Both Democrats and Republicans are seeking the political advantage on the energy issue, with most Congressional Republicans loudly calling for more offshore drilling and Democrats accusing the GOP of being too cozy with oil companies.

The Roll Call poll found that 38 percent of 2nd district voters blame oil companies for the high cost of gas — far and away the greatest number. And by a 22-point margin, the voters said they would prefer a Congressional candidate who advocates identifying and promoting alternative sources of energy over one who primarily advocates more offshore drilling.