The Justice Department’s anticipated investigation of Google will likely have to hone in on the company’s allegedly anticompetitive conduct such as its restrictive licensing agreements, not whether it’s being fair to competitors on its search engine.

DOJ antitrust enforcers are preparing to launch a probe into Google’s search practices, according to media reports. The plan immediately triggered comparisons to the European Union’s $2.7 billion antitrust fine against the Alphabet Inc.'s subsidiary in 2017 over claims that its alleged promotion of...