Jim McTague of Barron’s highlights U.S. Senate races in North Carolina and Iowa for his latest “D.C. Current” column, which focuses on Gallup’s latest measures.

Gallup has a gift for nerds like me who like to handicap elections — detailed reports on the political and economic environment in states with close U.S. Senate races this November. The data are available for free on the polling group’s Website gallup.com (under the tab Election 2014), and include everything from respondents’ confidence in the state and national economies to satisfaction with state tax levels and the performance of state government. The surveys are too new to assess their predictive abilities. But they offer a treasure trove too rich to be dismissed.

Last week, the score cards were released for North Carolina and Iowa, where candidates are in statistical dead heats. Gallup’s Editor in Chief Frank Newport told me that the site will continue updating and publishing these state score cards into October. …

… Newport says that both the North Carolina and Iowa U.S. Senate races will be great tests of the score cards’ effectiveness. In both places, a former member of the state legislature is taking on a member of Congress. We might see strong evidence of whom voters blame more for their woes: state officials or federal officials. …

… In North Carolina, GOP State House Speaker Thom Tillis is trying to unseat Democratic U.S. Sen. Kay Hagan, who herself unseated Republican Sen. Elizabeth Dole in 2008. Obama’s approval rate is at 41%, close to the national average. Trust in the state government is 51%, lower than the national average.

Confidence among Tar Heel voters in the U.S. economy is minus 20%. Confidence in the state’s economy is positive, but just barely, at 8%. Small wonder then that Tillis is trying to identify Hagan with Obama and that Hagan is running against the performance of the state’s Republican-controlled government. As in Iowa, the determining factor in this race could come down to whom voters fault for the state’s underwhelming economic performance — Obama or the state’s Republican legislators, Gallup notes.