Likening the nation’s top two office supply chains to “penguins on a melting iceberg,” a lawyer for Staples Inc. in opening statements on Monday defended the company’s proposed acquisition of Office Depot Inc. against federal regulators.

Staples’ lawyer, Weil Gotshal & Manges partner Diane Sullivan, painted Staples and Office Depot as two companies trying to survive in an increasingly digital age where documents are stored in clouds instead of cabinets. In spite of that landscape, where the companies are confronted with declining sales and rising behemoths such as Amazon Business, Sullivan said the Federal Trade Commission has challenged the proposed $6.3 billion acquisition based on a market view she characterized as “rigged,” “narrow” and “artificially inflated.”