WILMINGTON, Del.  One of the great truisms of 20th-century politics, attributed to the legendary House speaker Tip O’Neill, is that all politics is local. If this year tells us anything, though, it’s that O’Neill’s adage may now be as much a part of history as he is.

Just take the example of Christine O’Donnell, the Republican Senate candidate in Delaware. Ms. O’Donnell is ubiquitous on conservative cable shows and talk radio, with her candidacy hyped by the likes of Rush Limbaugh and the Tea Party Express, based in California. But you can barely find a trace of Ms. O’Donnell or her campaign in Delaware itself, a state that is smaller than some national parks.

Whatever else Ms. O’Donnell may symbolize, she stands for the idea that politics in the online age is increasingly borderless and can often be shaped more by national causes than by anything having to do with local constituents.

Ms. O’Donnell, a perennial protest candidate and conservative provocateur, became a celebrity among Tea Party types around the country in the weeks leading up to the Sept. 14 primary, in which she beat Representative Michael N. Castle, the party leadership’s preferred candidate, by about 3,500 votes. The bulk of the contributions her campaign has received have come from outside Delaware, according to the Center for Responsive Politics, and until this week she had no campaign office in the state. She and a few aides were working out of her town house.