As the Occupy Wall Street (OWS) demonstration enters its fourth week, one thing is certain: anyone who tells you that they know how much/whether the protest will grow and what, if any, impact it will have on the political climate and public policy is being disingenuous.

Social Movements: Hard to Predict

Point: We know from political science research that activist/protest movements are complex and hard to predict. Many factors affect whether a protest movement gains momentum or fades -- and each of the these factors is difficult to gauge. Hence readers/observers should evaluate instant-analysis offered on the 24-hour cable news networks MSNBC, CNN, and Fox by professionals who study protest & dissent and by lay pundits with the aforementioned complexity in mind: the instant-analysis probably will prove to be inaccurate, or in some cases, completely wrong.

Further, a more-illuminating question is: what can we learn from past socio-economic protests? I..E., are there any case studies of past protest movements that might provide clues regarding Occupy Wall Street's impact on the political culture and public policy?

Social Movements: Few Succeed

In the modern era in the United States, one over-arching theme or axiom from previous protest movements is that: 1) few succeed, and that those that do succeed often succeed because they effectively influenced and were absorbed by one of the United States' two major political parties. In the modern era, of course, that's meant the Democratic Party or Republican Party.

The above may displease ideological purists on the left in Occupy Wall Streets (and on the right in the Tea Party) but the harsh reality is the United States' electoral system favors absorption of succeeding socio-economic movements in to one of the two major political parties. The reasons? First, the U.S.'s winner-take-all congressional districts make it hard for narrow third-parties, such as a Populist/Working Class Party by Occupy Wall Street or the Tea Party, to win Congressional seats, and Congressional seats are one major outlet for national political power. Second, the same winner-take-all electoral system for presidential electoral votes used by almost all states, makes it even harder for a third party to win the U.S. presidency, the other major outlet for national political power.

In other words, history suggests that if Occupy Wall Street tries to form a third party, it will not succeed. Almost all third parties fail. And when social-economic protests do succeed, most of the time their interests are absorbed into one of the two major political parties.

Rare: An Issue That Triggers a Political Realignment

Of course, there are exceptions to the above axiom. Occasionally, a socio-economic movement becomes so strong that it realigns the political system, changing the balance of power between the two political parties, often after a realigning election. When this occurs, a new dominant majority coalition replaces an old dominant majority coalition. But again, understand that a realignment often takes decades to form, and there has to be a large issue/problem that's unsolved.

The last major realignment in the U.S.? The 1932 election, when the Democratic Party became the dominant majority party led by President Franklin D. Roosevelt's New Deal coalition, replacing the Republican Party's dominant majority coalition. The issue: taking public action to alleviate suffering caused by the Great Depression.

To be sure, much has happened socially, economically, and politically in the United States since the Democrats became the dominant majority party in 1932, including an increase in Independent voters, but the party distribution has basically remained the same: the Democrats still hold an edge in party identification, Republicans are second and Independents are third. Some polls today show Independents with the largest block of voters, but this is a misnomer: after probing, most Independents are either Leaning Democrats or Leaning Republicans.

Little Has Changed, Party System-Wise, Since 1932

Further, it may seem implausible to state that the party system of 1932 basically is still in place today, but that is the truth. Despite the enormous changes and events in 20th century U.S. history, the issues haven't been big enough to realign the electorate. Some de-alignment has occurred, but not a realignment.

Keep in mind that to realign the electorate the issue has to be huge. Before the Great Depression that triggered the 1932 realignment that made the Democratic Party the dominant majority party, the last issue to realign the electorate was the Civil War, which made Abraham Lincoln's Republican Party the dominant majority party in the 1860 election.

What's more, not even the culture-changing, controversial Vietnam War of the mid-1960s/early 1970s or the Watergate scandal and resignation of President Richard Nixon, R-Calif. in the mid-1970s -- the United States' two biggest crises since the Great Depression -- were big enough to realign the electorate.

Best Tack For Occupy Wall Street: Elect Democrats

Hence, from the history of third parties and social/economic protests we can see what the likely course for Occupy Wall Street will be, if it is to succeed.

Underscoring, at this stage no can predict whether it will succeed, but if it is to succeed, it probably will not be as a third party, and given its populist/social justice values, it probably will be absorbed by the Democratic Party. Further, at this stage popular support behind the income inequality / jobs /social justice issue that triggered Occupy Wall Street is not large enough to trigger a party realignment.

For the ideological purists in Occupy Wall Street, the above absorption scenario may be unacceptable or even detestable. The ideologues in Occupy Wall Street may believe their demands of increasing taxes on the upper-income adults (particularly those with adjusted gross incomes over $1 million), ending corporate welfare, supporting trade unionism / increasing the minimum wage, supporting social spending to create infrastructure jobs, creating affordable health care, and protecting Social Security and Medicare, and other demands, are more likely to be met by third party formation, but U.S. history suggests otherwise.

History shows that Occupy Wall Street's best tack to achieve its goals is to: elect as many Democrats as possible, elect as many Democrats who agree with the group's goals, and defeat as many Republicans as possible.