This article is part of David Leonhardt’s newsletter. You can sign up here to receive it each weekday.

Critics — and even supporters — of President Trump have such low expectations of him at this point that yesterday didn’t even feel shocking. But it should feel shocking.

The president has used the nation’s foreign policy to conduct a grubby political operation. Had Barack Obama, George W. Bush or any other president in memory done even a fraction of what Trump has done, the reaction would have been widespread fury, and not just from the opposing political party. But the Republican Party has chosen to abandon principle for fealty to power.

The best remaining hope is that voters will punish Republicans for their corrupt bargain.

For more …

The hearing showed the advantage of having skilled staff attorneys conduct most of the questioning, rather than having the hearing be dominated by grandstanding speeches from members of Congress. Daniel Goldman, a Democratic lawyer who did much of the questioning, “keeps the focus on the witness (not himself), and lets him tell the story,” Asha Rangappa, a former F.B.I. agent, noted as the hearing was happening.

Frida Ghitis, CNN: “The case against President Donald Trump is strong and reality-based. The Republican effort to defend him is weak and based on fiction.” My colleague Nicholas Kristof: “Why allow a president to get away with what would be a firing offense for anyone else?”

The Republican defense revolved around claiming “a vast conspiracy of deep state bureaucrats operating throughout the government and using the national media to further their agenda,” Jonathan Chait of New York magazine wrote. “As a matter of substance, [this defense] is almost nonexistent.” But Republicans aren’t so much making a rational case, Michelle Goldberg has pointed out, as they are simply trying to sow confusion.

Another Republican defense was that the witnesses were often describing secondhand information. And no wonder: Trump has refused to let aides with firsthand knowledge testify, which in and of itself seems to be evidence of guilt. “The president now claims that … he never intended to do anything wrong,” Neal Katyal wrote in The Times. “But the only way to test that claim is to permit witnesses to testify about what the president said at the time, and what he knew and asked about.”

A final defense is that the United States ultimately sent the foreign aid that Trump had held up to Ukraine. Yet he did so only after a whistleblower filed a complaint.