Exxon Mobil Corp. went to court Wednesday to challenge a government investigation of whether the company conspired to cover up its understanding of climate change, a sign the energy company is gearing up for a drawn-out legal battle with environmentalists and officials on the politically charged issue. The company filed court papers in Texas seeking to block a subpoena issued in March by the attorney general of the U.S. Virgin Islands, one of several government officials pursuing Exxon. Wednesday’s filing argues that the subpoena is an unwarranted fishing expedition into Exxon’s internal records that violates its constitutional rights...Both sides see this as a pivotal moment in a growing campaign by environmentalists to deploy a legal strategy used against tobacco companies in the 1990s by arguing that oil companies have long hidden what they know about climate change. Tobacco firms’ finances and credibility were badly damaged by lawsuits accusing them of hiding the truth about their products.