The House and Senate operate very differently, partly because their members differ in the length of their terms, as well as in their age and other characteristics. In this section, we will explore why constitutional rules affect the elections for the two types of representatives and the reason the two bodies function differently by design. We also look at campaign finance to better understand how legislators get elected and stay elected.

Understanding the House and Senate

The U.S. Constitution is very clear about who can be elected as a member of the House or Senate. A House member must be a U.S. citizen of at least seven years’ standing and at least twenty-five years old. Senators are required to have nine years’ standing as citizens and be at least thirty years old when sworn in. Representatives serve two-year terms, whereas senators serve six-year terms. Per the Supreme Court decision in U.S. Term Limits v. Thornton (1995), there are currently no term limits for either senators or representatives, despite efforts by many states to impose them in the mid-1990s.^[1]

House members are elected by the voters in their specific congressional districts. There are currently 435 congressional districts in the United States and thus 435 House members, and each state has a number of House districts roughly proportional to its share of the total U.S. population, with states guaranteed at least one House member. Two senators are elected by each state.

The structural and other differences between the House and Senate have practical consequences for the way the two chambers function. The House of Representatives has developed a stronger and more structured leadership than the Senate. Because its members serve short, two-year terms, they must regularly answer to the demands of their constituency when they run for election or reelection. Even House members of the same party in the same state will occasionally disagree on issues because of the different interests of their specific districts. Thus, the House can be highly partisan at times.

In contrast, members of the Senate are furthest from the demands and scrutiny of their constituents. Because of their longer six-year terms, they will see every member of the House face his or her constituents multiple times before they themselves are forced to seek reelection. Originally, when a state’s two U.S. senators were appointed by the state legislature, the Senate chamber’s distance from the electorate was even greater. Also, unlike members of the House who can seek the narrower interests of their district, senators must maintain a broader appeal in order to earn a majority of the votes across their entire state. In addition, the rules of the Senate allow individual members to slow down or stop legislation they dislike. These structural differences between the two chambers create real differences in the actions of their members. The heat of popular, sometimes fleeting, demands from constituents often glows red hot in the House. The Senate has the flexibility to allow these passions to cool. Dozens of major initiatives were passed by the House and had a willing president, for example, only to be defeated in the Senate. In 2012, the Buffett Rule would have implemented a minimum tax rate of 30 percent on wealthy Americans. Sixty senators had to agree to bring it to a vote, but the bill fell short of that number and died.^[2]

Similarly, although the ACA became widely known as “Obamacare,” the president did not send a piece of legislation to Capitol Hill; he asked Congress to write the bills. Both the House and Senate authored their own versions of the legislation. The House’s version was much bolder and larger in terms of establishing a national health care system. However, it did not stand a chance in the Senate, where a more moderate version of the legislation was introduced. In the end, House leaders saw the Senate version as preferable to doing nothing and ultimately supported it.

Incumbency Effects

Not surprisingly, the jungle of campaign financing regulations and loopholes is more easily navigated by incumbents in Congress than by newcomers. Incumbents are elected officials who currently hold an office. The amount of money they raise against their challengers demonstrates their advantage. In 2014, for example, the average Senate incumbent raised $12,144,933, whereas the average challenger raised only $1,223,566.^[3]

This is one of the many reasons incumbents win a large majority of congressional races each electoral cycle. Incumbents attract more money because people want to give to a winner. In the House, the percentage of incumbents winning reelection has hovered between 85 and 100 percent for the last half century. In the Senate, there is only slightly more variation, given the statewide nature of the race, but it is still a very high majority of incumbents who win reelection. As these rates show, even in the worst political environments, incumbents are very difficult to defeat. These rates have remained steady in election 2016-2020, and are expected to hold in the foreseeable future.

Historically, incumbents in both the House and the Senate enjoy high rates of reelection.

The historical difficulty of unseating an incumbent in the House or Senate is often referred to as the incumbent advantage or the incumbency effect. The advantage in financing is a huge part of this effect, but it is not the only important part. Incumbents often have a much higher level of name recognition. All things being equal, voters are far more likely to select the name of the person they recall seeing on television and hearing on the radio for the last few years than the name of a person they hardly know. And donors are more likely to want to give to a proven winner.

But more important is the way the party system itself privileges incumbents. A large percentage of congressional districts across the country are “safe seats” in uncompetitive districts, meaning candidates from a particular party are highly likely to consistently win the seat. This means the functional decision in these elections occurs during the primary, not in the general election. Political parties in general prefer to support incumbents in elections, because the general consensus is that incumbents are better candidates, and their record of success lends support to this conclusion. That said, while the political parties themselves to a degree control and regulate the primaries, popular individual candidates and challengers sometimes rule the day. This has especially been the case in recent years as conservative incumbents have been “primaried” by challengers more conservative than they.

Another reason incumbents wield a great advantage over their challengers is the state power they have at their disposal.^[5] One of the many responsibilities of a sitting congressperson is constituent casework. Constituents routinely reach out to their congressperson for powerful support to solve complex problems, such as applying for and tracking federal benefits or resolving immigration and citizenship challenges.^[6]

Incumbent members of Congress have paid staff, influence, and access to specialized information that can help their constituents in ways other persons cannot. And congresspersons are hardly reticent about their efforts to support their constituents. Often, they will publicize their casework on their websites or, in some cases, create television advertisements that boast of their helpfulness. Election history has demonstrated that this form of publicity is very effective in garnering the support of voters.

Local and National Elections

The importance of airing positive constituent casework during campaigns is a testament to the accuracy of saying, “All politics is local.” This phrase, attributed to former Speaker of the House Tip O’Neill (D-MA), essentially means that the most important motivations directing voters are rooted in local concerns. In general, this is true. People naturally feel more driven by the things that affect them on a daily basis. These are concerns like the quality of the roads, the availability of good jobs, and the cost and quality of public education. Good senators and representatives understand this and will seek to use their influence and power in office to affect these issues for the better. This is an age-old strategy for success in office and elections.

Political scientists have taken note of some voting patterns that appear to challenge this common assumption, however. In 1960, political scientist Angus Campbell proposed the surge-and-decline theory to explain these patterns.^[7]

Campbell noticed that since the Civil War, with the exception of 1934, the president’s party has consistently lost seats in Congress during the midterm elections. He proposed that the reason was a surge in political stimulation during presidential elections, which contributes to greater turnout and brings in voters who are ordinarily less interested in politics. These voters, Campbell argued, tend to favor the party holding the presidency. In contrast, midterm elections witness the opposite effect. They are less stimulating and have lower turnout because less-interested voters stay home. This shift, in Campbell’s theory, provides an advantage to the party not currently occupying the presidency.

In the decades since Campbell’s influential theory was published, a number of studies have challenged his conclusions. Nevertheless, the pattern of midterm elections benefiting the president’s opposition has persisted.^[8] Only in exceptional years has this pattern been broken: first in 1998 during President Bill Clinton’s second term and the Monica Lewinsky scandal, when exit polls indicated most voters opposed the idea of impeaching the president, and then again in 2002, following the 9/11 terrorist attacks and the ensuing declaration of a “war on terror.”

The evidence does suggest that national concerns, rather than local ones, can function as powerful motivators at the polls. Consider, for example, the role of the Iraq War in bringing about a Democratic rout of the Republicans in the House in 2006 and in the Senate in 2008. Unlike previous wars in Europe and Vietnam, the war in Iraq was fought by a very small percentage of the population.^[9] The vast majority of citizens were not soldiers, few had relatives fighting in the war, and most did not know anyone who directly suffered from the prolonged conflict. Voters in large numbers were motivated by the political and economic disaster of the war to vote for politicians they believed would end it.

Wars typically have the power to nationalize local elections. What makes the Iraq War different is that the overwhelming majority of voters had little to no intimate connection with the conflict and were motivated to vote for those who would end it. (credit: “Lipton sale”/Wikimedia Commons)

Congressional elections may be increasingly driven by national issues. Just two decades ago, straight-ticket, party-line voting was still relatively rare across most of the country.^[10] In much of the South, which began to vote overwhelmingly Republican in presidential elections during the 1960s and 1970s, Democrats were still commonly elected to the House and Senate. The candidates themselves and the important local issues, apart from party affiliation, were important drivers in congressional elections. This began to change in the 1980s and 1990s, as Democratic representatives across the region began to dwindle. And the South isn’t alone; areas in the Northeast and the Northwest have grown increasingly Democratic. Indeed, the 2014 midterm election was the most nationalized election in many decades. Voters who favor a particular party in a presidential election are now much more likely to also support that same party in House and Senate elections than was the case just a few decades ago.

Summary

Since the House is closest to its constituents because reelection is so frequent a need, it tends to be more easily led by fleeting public desires. In contrast, the Senate’s distance from its constituents allows it to act more deliberately. Each type of representative, however, must raise considerable sums of money in order to stay in office. Attempts by Congress to rein in campaign spending have largely failed. Nevertheless, incumbents tend to have the easiest time funding campaigns and retaining their seats. They also benefit from the way parties organize primary elections, which are designed to promote incumbency.