It was bad news for the voting public when Election Systems and Software, the nation’s largest voting machine company, announced last fall that it was acquiring the elections division of Diebold, the nation’s second-largest voting machine company.

The combination could mean that nearly 70 percent of the nation’s precincts would use machines made by a single company. If the deal is allowed to go through, it would make it harder for jurisdictions to bargain effectively on price and quality. The Justice Department should reject it as a violation of antitrust rules that is clearly not in the public’s interest.

The 2000 presidential election debacle in Florida, with its hanging chads and uncounted votes, highlighted the deep flaws in voting machine technology  and in the industry. That was in no small part because of a lack of robust competition. If the Diebold acquisition goes forward, competition would all but disappear.

Numerous studies have shown that electronic voting machines are particularly vulnerable to software glitches, intentional vote theft or sabotage. Having such a large percentage of the nation’s votes counted on machines made and serviced by a single company increases the vulnerability of the system.