The demand for change during the 2008 presidential campaign is also evident in U.S. House and Senate races as Democrats are expected to increase their control of Congress. Polls indicate that voters prefer Democrats on various issues, such as the Iraq war, the economy, and energy, and feel that the country is heading in the wrong direction as President George W. Bush's term comes to a close. Despite the challenges faced by Democrats, including the low approval rating of the divided Congress, where Democrats gained control in 2007, Republicans have managed to hinder Democratic efforts on issues like withdrawing from Iraq. Stu Rothenberg of the nonpartisan Rothenberg Political Report stated that the public is seeking change. He explained that when voters consider who is in power, they primarily focus on the president rather than Congress. Rothenberg noted that voters tend to express their frustration by voting against the president's party. Senator Barack Obama of Illinois gained momentum in the Democratic presidential race by promoting a message of "hope and change" in Washington, despite facing challenges posed by political conflicts. Obama's message of "change" was so well-received that both his Democratic rival, Sen. Hillary Clinton, and the presumptive Republican nominee, Sen. John McCain, have adopted it. In November, voters will not only choose the next president to succeed Bush, but also elect one-third of the Senate and the entire House of Representatives. Democrats currently hold a slight majority in the Senate, 51-49, and in the House, 233-198 with four vacancies. It is anticipated that Democrats will pick up a few seats in both chambers, and there is a slim possibility of reaching the 60-seat threshold in the Senate to overcome Republican filibusters. The most recent time that either party had a Senate majority that could not be filibustered was in 1977-78 when the Democrats were in power. According to Jennifer Duffy from the Cook Political Report, there is a possibility that Democrats could reach 60 seats if everything goes well, but the chances are low due to the difficult political climate. There are 23 Senate seats up for election, with five of them currently held by retiring Republicans and others facing strong competition. All 12 Senate Democrats who are up for re-election are predicted to win, according to Senator John Ensign of Nevada, who is the chairman of the Senate Republican campaign committee. Ensign stated that a successful outcome for Republicans would be to maintain 47 or 48 seats, compared to the current 49. However, he doesn't believe that Democrats will reach 60 seats. On the other hand, Senator Charles Schumer of New York, who is the chairman of the Senate Democratic campaign committee, expressed optimism about the direction things are moving in for Democrats. Despite Democrats having more fundraising success and fewer congressional retirements than Republicans, they are worried about potential repercussions from the heated Obama-Clinton competition in the Democratic primary. House Democratic campaign committee chairman Rep. Chris Van Hollen expressed concerns about the lasting impact of internal party conflicts on the November election. Although he does not believe it will result in Democrats losing control of Congress, it could hinder their efforts to gain more seats. According to Andrew Kohut of the Pew Research Center, a strong performance by McCain in the presidential race could prevent further Republican losses in Congress. Kohut stated that the top of the ticket is very important because McCain performs well with independents, who often determine the outcome of elections. Democrats are aiming to counter any assertion that McCain or other Republicans represent "change" by linking them to Bush, who has low approval ratings. Van Hollen noted that even though Bush is not running this year, his presence still influences the elections. House Republicans must provide explanations for their seven years of supporting unsuccessful Iraq and economic policies. Rep. Tom Cole, the chairman of the House Republican campaign committee from Oklahoma, dismissed such concerns by stating that he believes their prospects have been underestimated. He pointed out that Democrats gained control of Congress in 2006 by blaming Republicans for various issues, such as the Iraq war, economic challenges, and high gas prices. Cole mentioned that now that Democrats have control of both the House and Senate, they also bear some responsibility for the negative perceptions of Washington.