and Freedom Party). Factors reinforcing the two party system include: The traditional American electoral format of single-member districts where the candidate with the most votes wins (known as the "first-past-the-post" system), which according to Duverger's law favors the two-party system. This is in contrast to multi-seat electoral districts and proportional representation found in some other democracies. the 19th century innovation of printing "party tickets" to pass out to prospective voters to cast in ballot boxes (originally, voters went to the polls and publicly stated which candidate they supported), "consolidated the power of the major parties". Printed party "tickets" (ballots) were eventually replaced by uniform ballots provided by the state, when states began to adopt the Australian Secret Ballot Method. This gave state legislatures—dominated by Democrats and Republicans—the opportunity to handicap new rising parties with ballot access laws requiring a large number of petition signatures from citizens and giving the petitioners a short length of time to gather the signatures. Political pressure groups Special interest groups advocate the cause of their specific constituency. Business organizations, for example, will favor low corporate taxes and restrictions on the right to strike, whereas labor unions will support minimum wage legislation and protection for collective bargaining. Other private interest groups, such as churches and ethnic groups, are more concerned about broader issues of policy that can affect their organizations or their beliefs. One type of private interest group that has grown in number and influence in recent years is the political action committee or PAC. These are independent groups, organized around a single issue or set of issues, which contribute money to political campaigns for United States Congress or the presidency. PACs are limited in the amounts they can contribute directly to candidates in federal elections. There are no restrictions, however, on the amounts PACs can spend independently to advocate a point of view or to urge the election of candidates to office. As of 2008, there were 4,292 PACs operating in the US. The number of interest groups has mushroomed, with more and more of them operating offices in Washington, D.C., and representing themselves directly to Congress and federal agencies. Many organizations that keep an eye on Washington seek financial and moral support from ordinary citizens. Since many of them focus on a narrow set of concerns or even on a single issue, and often a single issue of enormous emotional weight, they compete