The merger between XM Radio and Sirius is now a step closer to being consummated after the Department of Justice greenlighted the deal. Announced in February 2007, the merger has been held up over antitrust concerns, and the Federal Communications Commission still has to approve the deal.

"After a careful and thorough review of the proposed transaction, the Division concluded that the evidence does not demonstrate that the proposed merger of XM and Sirius is likely to substantially lessen competition, and that the transaction therefore is not likely to harm consumers," the DoJ's Antitrust Division said in its announcement.

The DoJ based its decision on a handful of factors, all of which boiled down to its belief that market conditions would prevent the combined satellite radio company from raising prices. Perhaps the largest factor weighing in favor of the merger is that the two companies don't compete for existing customers. While XM and Sirius obviously try to win over new converts from the non-satellite-loving masses, hardware incompatibilities mean that there's little to no crossover.

There's also a competitive market for "alternative services," the DoJ believes. XM and Sirius have argued that traditional terrestrial radio, HD radio, MP3 players, and other wireless technologies provide sufficient competition that a combined satellite radio provider would still face (terrestrial broadcasters have disagreed). The DoJ is certain that those alternatives would prevent Sirius and XM from jacking up prices in the wake of a merger.

Given the hardware incompatibilities between the two services, it may be a while before subscribers benefit from the combined entity. New receivers capable of getting programming from both providers should hit the market fairly quickly; retrofitting current gear to take advantage of programming from both XM and Sirius will be more challenging.

If the merger doesn't result in a morass of price increases and hardware incompatibilities, it should ultimately benefit consumers. Right now, programming from the likes of the NFL, Major League Baseball, Howard Stern, and others is spread across the two services. Consumers would no longer be faced with choosing baseball over football with the companies combined.

With the DoJ on board, the only remaining obstacle is the Federal Communications Commission, which must also approve the deal. The FCC is unlikely to veto it now that Justice has vetted the merger for antitrust concerns, but the possibility remains that the Commission will impose conditions on the merger, including pricing, a la carte programming, and service bundles.