The social groups to which individuals belong can also impact their opinion on politics. For example, a church and faith community can be a strong influence. The gender, race, age, ethnicity, or geographic region of individuals can play a role in their perception of candidates and issues. Membership in an advocacy group will likely influence an individual to align his or her position with that of the group. Professional groups—unions, for example—frequently educate their membership on particular industry-related issues, which can persuade members to vote a certain way.
Additionally, the media a person reads or watches can be a major factor in how that individual views an issue. With modern access to a vast amount of news sources, people often choose to rely on specific people in the media to guide them through the political world. Political elites such as news anchors, reporters, talk show hosts, political pundits, and politicians can wield an enormous amount of influence on many voters. This is especially true for voters whose views are already similar to those of the political elite they follow. The news media plays a role through agenda setting, the process by which the media determines what issues people think about and are concerned about. Social media outlets like Facebook and Twitter can influence opinion by reinforcing attitudes. With both sites, news items or notices appear in a member's news feed based on complex algorithms tailored to the individual based on personal characteristics and expressed likes and dislikes. By providing items that seem to reflect the person's interests and preferences, the site can strengthen the individual's beliefs and attitudes.
Throughout U.S. history, certain major events have redirected public opinion by affecting large segments of the American population to such a degree that some people changed their minds on key issues. For example, during the Great Depression in the 1930s, many Americans wanted the federal government to take a more active role in overseeing the economy. After the terrorist attacks on September 11, 2001, Americans were more likely to support restrictions on certain groups' civil liberties if it meant a safer country. Those attacks also led to a spike in the approval ratings of President George W. Bush. This result reflects what political scientists call the rally effect, a phenomenon in which approval of the job a president is doing tends to increase at times of war or international crisis, as the public rallies around the flag in the person of the president.
At its core, public opinion is extremely personal. People believe in something because it aligns with the idea that they have of how government should work. Much of the time, people's self-interest is tied to their view of government and policy. People consider such questions as the following: How will this change to tax policy affect my paycheck? How will this law affect my family's safety? How will this policy affect my rights and freedoms?