In politics, a big tent or catch-all party is a political party seeking to attract people with diverse viewpoints and thus appeal to more of the electorate. This is accomplished by appealing to a very limited number of issues, characteristics and/or goals, yet, capable enough to create the degree of unity necessary to fulfill said objectives. The big tent approach is opposed to ideological cohesiveness, conversely advocating multiple ideologies and views within a party.
In the United States, during the latter half of the 19th century and beginning of the 20th, the Republican Party boasted membership of big business interests, laborers (both of whom supported the GOP's tariff strategy) as well as many African Americans, due to Republican Abraham Lincoln's abolition of slavery and the party's stance on civil rights.
Another example of the big tent approach was the New Deal coalition led by the Democratic Party, which formed in support of Franklin D. Roosevelt's New Deal policies from 1930s until 1960s. This coalition brought together labor unions, southern Dixiecrats, progressives, and others in support of FDR's economic program, even though these groups strongly disagreed on other issues.
The Libertarian Party, following the 1974 Dallas Accord, embraced the big tent idea to the extent it ensured that the anarchist-capitalist views would not be excluded from the majority minarchist party. The Republican Liberty Caucus and similar groups aim to shift the US Republican Party's "center of the tent" towards Goldwater-Reagan ideals and those of libertarian Ron Paul.