It’s a truism in politics to say that “all politics is local”, but truisms are truisms because they’re usually true. In this case it’s right on the money. And the precinct is the most “local” organizational unit in American politics.
Put simply, a "precinct" is essentially your neighborhood. It’s a geographic area with specific boundaries, (usually defined by your state), that surrounds the place where you go to vote. The name of your precinct is listed on your voter registration card.
There are more than 203,000 precincts in the United States, each with an average of about 1,000 registered voters. Politically, they represent the building blocks that comprise all other political districts in America, (whether local council, state legislature or congress). And precincts are where the voters are – which means that’s where the power is in our political system.
Political influence goes to those who are the most organized at the precinct (or neighborhood) level. And good grassroots organization emphasizes the important role that precincts play and the idea that all politics is local by focusing on individuals who are willing to identify and organize others in their own neighborhoods.
That goes for campaigns, grassroots lobbying efforts and gaining influence in the Republican Party.
It's another case of "think globally, act locally".
- The four rules to winning an election 
- A menu of effective grassroots activities 
- Three venues for conservative grassroots organization 
(You can find tips like this and much more in my “Grassroots 101: Grassroots Training Series ”.)