WASHINGTON — When the nation’s antitrust laws were created more than a century ago, they were aimed at taking on industries such as Big Oil.

But technology giants like Amazon, Facebook, Google and Apple, which dominate e-commerce, social networks, online advertising and search, have risen in ways unforeseen by the laws. In recent decades, the courts have also interpreted the rules more narrowly.

On Monday, a pair of rulings dismissing federal and state antitrust lawsuits against Facebook renewed questions about whether the laws were suited to taking on tech power. A federal judge threw out the federal suit because, he said, the Federal Trade Commission had not supported its claims that Facebook holds a dominant market share, and he said the states had waited too long to make their case.

The decisions underlined how cautious and conservative courts could slow an increasingly aggressive push by lawmakers, regulators and the White House to restrain the tech companies, fueling calls for Congress to revamp the rules and provide regulators with more legal tools to take on the tech firms.

David Cicilline, a Democrat of Rhode Island, said the country needed a “massive overhaul of our antitrust laws and significant updates to our competition system” to police the biggest technology companies.

Moments later, Representative Ken Buck, a Colorado Republican, agreed. He called for lawmakers to adapt antitrust laws to fit the business models of Silicon Valley companies.

This week’s rulings have now put the pressure on lawmakers to push through a recently proposed package of legislation that would rewrite key aspects of monopoly laws to make some of the tech giants’ business practices illegal.

“This is going to strengthen the case for legislation,” said Herbert Hovenkamp, an antitrust expert at the University of Pennsylvania Law School. “It seems to be proof that the antitrust laws are not up to the challenge.”

introduced this month and passed the House Judiciary Committee last week. The bills would make it harder for the major tech companies to buy nascent competitors and to give preference to their own services on their platforms, and ban them from using their dominance in one business to gain the upper hand in another.

including Lina Khan, a scholar whom President Biden named this month to run the F.T.C. — have argued that a broader definition of consumer welfare, beyond prices, should be applied. Consumer harm, they have said, can also be evident in reduced product quality, like Facebook users suffering a loss of privacy when their personal data is harvested and used for targeted ads.

In one of his rulings on Monday, Judge James E. Boasberg of U.S. District Court for the District of Columbia said Facebook’s business model had made it especially difficult for the government to meet the standard for going forward with the case.

The government, Judge Boasberg said, had not presented enough evidence that Facebook held monopoly power. Among the difficulties he highlighted was that Facebook did not charge its users for access to its site, meaning its market share could not be assessed through revenue. The government had not found a good alternative measure to make its case, he said.

He also ruled against another part of the F.T.C.’s lawsuit, concerning how Facebook polices the use of data generated by its product, while citing the kind of conservative antitrust doctrine that critics say is out of step with the technology industry’s business practices.

The F.T.C., which brought the federal antitrust suit against Facebook in December, can file a new complaint that addresses the judge’s concerns within 30 days. State attorneys general can appeal Judge Boasberg’s second ruling dismissing a similar case.