(CNN) — Two years ago, Facebook changed its mission statement to focus on “bringing the world closer together.” On Tuesday, it finally appeared to accomplish that lofty goal for the political world, at least, as Republican and Democrat lawmakers united in bipartisan distrust of the social media giant.

“Facebook is dangerous,” Ohio Sen. Sherrod Brown, a Democrat and ranking member on the Senate Banking Committee, said in prepared remarks to kick off a hearing on Facebook’s proposal for a new digital currency, called Libra. “Like a toddler who has gotten his hands on a book of matches, Facebook has burned down the house over and over, and called every arson a learning experience.”

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Sen. Martha McSally, an Arizona Republican, sounded a similarly damning note later in the hearing. “I don’t trust you guys,” she said. “Instead of cleaning up your house, now you’re launching into a another business model.”

The tense hearing came on a day of back-to-back grillings for Silicon Valley executives on Capitol Hill.

Later on Tuesday, executives from Facebook, Google, Amazon and Apple are set to testify at a House antitrust hearing examining the consequences of their growing market power. On Wednesday, Facebook will face more questions over Libra from the House Financial Services committee.

The House Judiciary Committee is holding the hearing as part of a “top-to-bottom” antitrust investigation of the tech industry announced last month. An earlier hearing focused on the tech industry’s impact on the news industry. The latest hearing will focus on “innovation and entrepreneurship.”

Among those scheduled to testify on Tuesday are: Matt Perault, head of global policy development at Facebook; Adam Cohen, director of economic policy at Google; Nate Sutton, associate general counsel for competition at Amazon; and Kyle Andeer, VP of corporate law at Apple.

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Once viewed in purely glowing terms as icons of American innovation, these companies now face mounting calls from lawmakers, presidential candidates and even some tech industry insiders to be broken up and have their immense power checked. In addition to the House antitrust probe, two federal agencies are said to be paving the way for potential investigations into the four companies’ market dominance.

Despite the growing scrutiny, Big Tech has continued to move forward with efforts to get even bigger.

In the weeks since news of the potential US antitrust probes first broke, Google announced a $2.6 billion acquisition to bolster its cloud computing division, Jeff Bezos teased plans for Amazon to spend billions to launch thousands of satellites that provide broadband internet, and Facebook unveiled Libra with the potential to change financial and payment systems around the world.

If the first Libra hearing is any indication, this aggressive approach to expansion may only make it harder for companies like Facebook to win over skeptical politicians at the antitrust hearing. In recent weeks, the tech companies have trotted out multiple lines of defense in what could be a preview of the talking points at the upcoming hearing.

Google CEO Sundar Pichai told CNN Business last month that being bigger “does offer many benefits,” including the ability to invest in cutting edge technologies such as artificial intelligence and quantum computing. Similarly, Facebook CEO Mark Zuckerberg recently said being bigger makes it possible for the company to invest in preventing the spread of misinformation and election interference. Execs from both companies have also suggested that breaking up US tech companies could benefit businesses in other countries, namely China.

The shift in DC’s sentiment toward Silicon Valley has been a long time coming. Since the 2016 election, internet giants such as Facebook and Google have been embroiled in a series of PR crises over data privacy, the role their platforms played in election meddling, and the spread of misinformation, raising concerns about the full impact these powerful businesses are having on society. At the same time, these internet companies have increasingly expanded beyond their original markets into new categories, including healthcare, entertainment and transportation.

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