As the city kicks off its annual Independence Day celebration, it's important to remember that there is little freedom without participation. And freedom was threatened last year not only by voter-ID laws, which set up barriers to legitimate democratic participation, but also by confusion at the polls in Philadelphia, where thoughtful revolutionaries once gathered to write the Declaration of Independence.

Seven months after the Nov. 6 election, three separate investigations - by Mayor Nutter, City Controller Alan Butkovitz, and the City Commissioners - have examined why more than 27,000 city voters had to use provisional paper ballots instead of voting machines. A little more than half of them weren't properly registered or had shown up at the wrong polling place, in which case provisional ballots were appropriate. But far too many problems were caused by official incompetence.

Investigators concluded that better training of election workers is needed. Luckily, the City Commissioners, the elected officials who run Philadelphia elections, have improved training and are strengthening central controls. But that's not enough.

According to the controller's analysis, 40 percent of the voters who had to cast paper ballots did so "because of poll worker mistakes or errors in the creation of polling books." These voters never should have been turned away from voting machines and forced to vote with paper ballots, which aren't counted on Election Day and can end up being thrown out.

The commissioners blame their poll book errors on a state database "glitch." But neither they nor state officials have adequately explained how that happened so it can be prevented in the future.

Nearly 5,000 voters had to cast paper ballots because poll workers didn't properly check the poll books. The workers are being advised that they should double-check the books and the names when they can't find voters, which seems to go without saying.

Unfortunately, the commissioners don't have the power to fire workers who consistently fail to meet standards. That's because the poll workers are elected, at least nominally. Returns show that many assume office with zero votes, which means they aren't even voting for themselves.

Many poll workers put in a 13-hour day for about $100 and do their jobs well out of a sense of civic pride. But those who are too indifferent to properly check a poll book or pay attention to their training should be sent on their way. The legislature should make that possible by making these appointed positions.

The investigations of the election won't mean a thing if they don't lead to reform of this rickety system, which tends to get patched but never fully repaired by a city that has historically underfunded it.

Election Commissioners Stephanie Singer and Al Schmidt, who were elected as reformers, failed their first test on Nov. 6, while Chairman Anthony Clark was missing in action as usual. They have to do better. And the legislature, the mayor, and City Council need to help them fix this mess and protect Philadelphians' right to vote.