The streaming video provider wants to block CBS — and, presumably, other broadcasters — from making good on a threat to file suits across the country to address the same issue: whether Aereo violates their copyrights. That’s already being debated at the U.S. District Court in New York, Aereo’s only current market. But CBS chief Les Moonves said last week that as Aereo expands — including in Boston this month — “we’ll sue them again” in different jurisdictions. “We’ll follow it.” Aereo asked the New York court this morning for a declaratory judgment that would try to establish it as the sole locale for the legal battle. Aereo plans to enter 21 additional markets this year after Boston and says that multiple suits “would be highly inefficient and a waste of judicial resources” since it would “involve the same technology, involve the same witnesses, and implicate the same legal and factual issues” raised in New York. Broadcasters may want to find a friendlier venue after the U.S. Appeals Court in New York rejected their effort to shut Aereo during the trial. Justices said that there was a good chance that Aereo could win. The company says that it leases antennas, giving consumers the opportunity to exercise their right to watch programming that’s already distributed for free over the air. “The fact that CBS did not prevail in their efforts to enjoin Aereo in their existing federal lawsuit does not entitle them to a do-over in another jurisdiction,” company spokesperson Virginia Lam says.