The Supreme Court (Winter v. Natural Resources Defense Council ) voted 5-4 to rescind bans on sonar use  in training exercises off the California coast. Those bans were implemented by lower federal courts. The ruling states that the lower courts exceeded their authority in those actions.
The bans were in place presumably to protect sea life from the negative effects of sonar use… effects that have been researched by organizations like the National Resources Defense Council (NRDC ). I can not speak directly to the integrity of the research, but it seems the concerns bear consideration. Perhaps not a knee-jerk response, since sonar has been in regular use for decades now, but enough careful consideration that if sea life is truly being impacted, specifically by excessive noise (and sonar is not the only source of noise that is produced by human activities in the ocean), then we can look at appropriate legal imperatives to provide adequate protection without hog-tying the Navy from being adequately prepared for real battles.
The Court was not, in this case, judging the merits of the environmental concerns, but rather the authority of the lower courts. This is actually good news (sort of, since one vote could have swayed the decision) in that the High Court sees the need to recognize the boundaries of judicial responsibility.
Now, let’s address these issues in Congress if truly needed. We can also take the time to examine internationally agreed upon rules and the policies of other countries  as we determine appropriate policy here in the US. But key here must be the fact that training exercises, with as much live equipment as possible, is critical to the success of our military. While we may at times risk impact to the balance of the current ecology, and must consider that carefully, protecting our country, and those who serve, is paramount.