PRINCETON, NJ -- Two months ahead of the midterm elections that may very well change the balance of power in Congress, four in 10 Americans say the specific party that controls Congress matters a great deal to them, while 29% say it matters a moderate amount and another 30% say it generally doesn't matter to them.

The 40% of national adults now highly concerned about control of Capitol Hill equals what Gallup found a month before the 2002 midterms, but is lower than the 49% seen in late October 2010.

While the views of Democrats (including independents who lean Democratic) on this question have been steady across the three midterms -- roughly 45% each year have said the party in control mattered a great deal to them -- Republicans' concern has varied. Currently, 43% of Republicans (including Republican leaners) say party control matters a great deal. It was a whopping 61% in 2010, but that was up from 42% in 2002.

The 2002 and 2010 elections were favorable to Republicans, as the GOP retained majority control of the U.S. House of Representatives and regained control of the Senate in 2002, and recaptured control of the House in 2010 with an enormous seat gain. Thus, while rank-and-file Republicans' concern about party control is not nearly as high today as it was in 2010, when Democrats controlled both houses, it is comparable to 2002 -- which could suggest that conditions are still favorable for the GOP. Missing from this midterm trend, however, is 2006, which was a strong Democratic year. Therefore, it is not entirely clear how levels of concern on this question relate to each party's performance.

These results are from the 2014 update of Gallup's annual Governance survey, conducted Sept. 4-7.

Close to Four in 10 Also Knowledgeable About Control of Congress

The same poll asked respondents to identify the party currently holding a majority of seats in the U.S. Senate as well as in the U.S. House of Representatives. About half of Americans can correctly identify the majority party for each: 49% say the Democrats control the Senate, and 51% say the Republicans control the House. Somewhat fewer -- 36% -- can correctly identify the majority in both chambers, although this knowledge is somewhat higher, at 41%, among registered voters.

Another 14% of Americans are aware that party control of Congress is divided, but match each party to the wrong chamber, believing Republicans control the Senate and Democrats control the House.

A relatively large subset of Americans, 28%, can correctly identify the majority party for only one chamber (while being wrong or unsure about the other), while 22% are either unsure about both, or name the wrong party for one chamber and are unsure about the other.

Americans who are knowledgeable about who controls each house of Congress are significantly more likely than others to say party control of Congress matters greatly to them: 55% of the well-informed group say this, versus about a third or less of those who can't properly identify party control. This highlights the divide in midterm politics between the politically concerned and informed subset of Americans -- a proportion similar to the typical midterm turnout rate, near 40% -- and the rest of the population that is less engaged politically.