Although presidential elections occur every 4 years, many people feel that they do not have a true understanding of how presidential campaigns operate.

The winner in the November general election is almost certain to be either the Republican or the Democratic nominee. A minor-party or independent candidate, such as George Wallace in 1968, John Anderson in 1980, or Ross Perot in 1992 and 1996, can draw votes away from the major-party nominees but stands almost no chance of defeating them.

A major-party nominee has the critical advantage of support from the party faithful. Earlier in the twentieth century, this support was so firm and steady that the victory of the stronger party's candidate was almost a certainty. Warren G. Harding accepted the 1920 Republican nomination at his Ohio home, stayed there throughout most of the campaign, and won a full victory simply because most of the voters of his time were Republicans. Party loyalty has declined in recent decades, but more than two-thirds of the nation's voters still identify themselves as Democrats or Republicans, and most of them support their party's presidential candidate. Even Democrat George McGovern, who had the lowest level of party support among recent nominees, was backed in 1972 by nearly 60 percent of his party's voters.

Presidential candidates act strategically. In deciding whether to pursue a course of action, they try to estimate its likely impact on the voters. During the 1992 campaign, a sign on the wall of Clinton's headquarters in Little Rock read, "The economy, Stupid." The slogan was the idea of James Carville, Clinton's chief strategist, and was meant as a reminder to the candidate and the staff to keep the campaign focused on the nation's slow-moving economy, which ultimately was the issue that defeated Bush. As in 1980, when Jimmy Carter lost to Ronald Reagan during tough economic times, the voters were motivated largely by a desire for change.

Candidates try to project a strong leadership image. Whether voters accept this image, however, depends more on external factors than on a candidate's personal characteristics. In 1991, after the Gulf War, bush's approval rating reached 91 percent, the highest level recorded since polling began in the 1930s. A year later, with the nation's economy in trouble, Bush's approval rating dropped below 40 percent. Bush tried to stir images of his strong leadership of the war, but voters remained concerned about the economy.

The candidates' strategies are shaped by many considerations, including the constitutional provision that each state shall have electoral votes equal in number to its representation in Congress. Each state thus gets two electoral votes for its Senate representation and a varying number of electoral votes depending on its House representation. Altogether, there are 538 electoral votes (including three for the District of Columbia, even though it has no voting representatives in Congress). To win the presidency, a candidate must receive at least 270 votes, an electoral majority.

Candidates are particularly concerned with winning the states which have the largest population, such as California (with 54 electoral votes), New York (33), Texas (32), Florida (25), Pensylvania (23), Illinois (22), and Ohio (21). Victory in the eleven largest states alone would provide an electoral majority, and presidential candidates therefore spend most of their time campaigning in those states. Clinton received only 43 percent of the popular vote in 1992, compared with Bush's 38 percent and Perot's 19 percent; but Clinton won in states that gave him an overwhelming 370 electoral votes, compared with 168 for Bush and none for Perot.

虽然总统竞争每四年举行一次，但是许多人感到对竞选大战的运作没有真正的理解。

11月份大选的获胜者几乎肯定是共和党或民主党的提名者。小党派或独立候选人，如1968年的乔治·华莱士，1980年的约翰·安德森或1992年和1996年的罗丝·佩罗，可能从大党的提名人那里拉走了一些选票，但几乎没有人可能战胜他们。

大党提名人具有得到党的忠实信徒支持这一关键的优势。20世纪早期，这种支持是如此坚定、可靠，以至于较大党派候选人的胜利几乎是肯定的。华伦·G·哈定在俄亥俄州的家乡接受了1920年共和党的提名，并且在竞选大战大部分时间里都呆在俄亥俄。他大获全胜只是因为当时投票的大部分是共和党党员。在近几十年内，党员对党派的忠诚削弱了，但2/3强的国家的投票人依然认为他们自己是共和党人或民主党人，他们大多支持自己党派的总统候选人。即使是近年来拥有最低水平党派支持的民主人乔治·麦戈尔，在1972年仍得到了近60％本党派投票人的支持。

总统候选人的行为颇讲究策略。在决定是否遵循一项行动方针时，他们要尽量估计一下该方针对投票人可能具有的影响。在1992年竞选大战期间，小石城克林顿竞选总部的墙上有一个牌子，上面写着"经济、蠢货"。这条标语是克林顿的首席战略詹姆斯·卡维尔的，主意，作为候选人和竞选班子全体成员的警世语，使这场竞选大战集中在国家缓慢增涨的经济上，这成为最后击败布什的策略。如同在1980年的经济困难时期，吉米·卡特输给了罗纳德·里根，投票人的积极性主要来源于意图改变的愿望。

候选人尽办突出表现一种强有力的领导形象。然而，投票人是否接受这一形象，比起候选人的个人特点来更要依靠外部因素。在1991年海湾战争后，布什的支持率达到91％，这是本世纪30年代开始民意测验以来的最高记录。一年后，因国民经济陷入困境，布什的支持率降低到40％以下。布什尽力去激起人们对他在战争时期强有力的领导形象的回忆，但投标票人依然关心经济问题。

候选人的策略的形成要考虑到许多因素，包括宪法的这一条款：每个州具有的选举人的票数与其在国会中的代表人数相同。因此，每个州因其参议院代表得到两张选举人票，依靠其众议院代表得到不同数量的选举人票。总共有538张选举人票。要赢得总统职务，一个候选人必须得到选举的多数票，即270张选票。

候选人特别关注是否能赢得人口最多的州，如加利福尼亚州（有54张选举人票）、纽约州（33张）、得克萨斯州（32张）、佛罗里达州（25张）、宾夕法尼亚州（23张）、伊里诺伊斯州（22张）和俄亥俄州（21张）。仅在11个最大的州的胜利就可提供选举的大多数，因此总统候选人在那些州花费大部分时间进行活动。1992年，克林顿只得到43％的大众选票，相比之下布什得到38％，佩罗19％。但克林顿获取支持的州给了压倒优势的370张选举人票，相比之下给了布什168张，佩罗一张也没有。