“Well, when the president does it, that means that it is not illegal.” — Richard M. Nixon (1913-1994)

As public hearings on impeachment begin this week, we will see the case for and the case against impeaching President Donald Trump. The facts are largely undisputed, but each side has its version of them.

The Democrats will argue that in his July 25, 2019 telephone call with his Ukrainian counterpart, seen in the context of months of negotiations between American and Ukrainian diplomats, Trump made it known that if the Ukrainian government wanted the $391 million in military and financial aid that Congress authorized and ordered, it first must offer, or announce that it was seeking, dirt on his likely 2020 political opponent, former Vice President Joe Biden or his son Hunter. That implicates a presidential violation of two federal statutes: One is the prohibition of solicitation of campaign help from a foreign government, and the other is the prohibition of bribery.

Federal election laws prohibit as criminal the mere solicitation of foreign help for a federal political campaign, whether the aid arrives or not. Federal law also prohibits and defines as bribery the intentional withholding or offering to withhold the performance of an official duty until a thing of value arrives, whether the thing of value arrives or not. Solicitation of foreign campaign assistance and bribery are the rare federal crimes that are defined by an attempt or an offer to commit them, even if they are never consummated.

All this is magnified, the Democrats will argue, by the immediacy of Ukraine’s financial and military needs. Since 2014, Ukraine has been fighting a bloody war with Russia, resulting in the deaths of 13,000 Ukrainians. In that year, Russia invaded the Ukrainian province of Crimea, which Russia continues to occupy. Since the end of World War II, the stated American policy toward Russia has been to resist and to help allies resist its territorial expansion.

The Democrats will also argue that Trump’s orders to executive branch employees to dishonor congressional subpoenas constitute the crime of obstruction of Congress. This is what New York Yankees pitching great Roger Clemens was tried for when he was acquitted of lying to Congress about the contents of his urine. All of these crimes — solicitation, bribery and obstruction — are subsumed under the constitutional rubric of high crimes and misdemeanors or bribery. These constitute two of the three permissible bases for impeachment.

None of these crimes requires pressure, coercion or success. Congress considers them so odious to our system that merely offering to commit them constitutes guilt. Presidents Richard Nixon and Bill Clinton both were charged with obstruction of Congress by ordering subordinates to refuse to cooperate with congressional investigators — even though many of them did cooperate.

The Republicans will argue that under the Constitution, the president — not Congress — sets the foreign policy of the nation. In foreign relations, the Supreme Court has ruled, Congress is limited to declaring war, appropriating funds, ratifying treaties and confirming ambassadors. All else foreign is presidential. Thus, whatever Trump wanted of the Ukrainian government, unless there is proof of evil intent, he was free to ask for. They will argue that there is no evidence of evil intent such as self-dealing or harming an ally or frustrating a congressional purpose.

Republicans will also argue that the impeachment process is irretrievably compromised by the personal involvement, partisan advocacy and secretive methods of the chairman of the House Select Committee on Intelligence, Rep. Adam Schiff, D-Calif. From this, they will argue that Schiff, and the evidence he developed, should be excluded from the proceedings. As well, to House Republicans, the crimes of illegal solicitation, bribery and obstruction of Congress require proof of Trump’s guilty state of mind, and such proofs are lacking.

Stated differently, Republicans will contend that because the president was ignorant of federal law and ignorant of his constitutional obligations to spend money as and when Congress directed, he cannot be punished for what he did not know.

This is dangerously close to the Nixonian view of the American presidency — that the president can do no wrong. Of course, Republicans will not state this plainly, as the lessons of Watergate and Nixon’s resignation have soundly and universally repudiated that view.

Finally, Republicans will argue that impeachment cheats democracy. Here they are correct. However, that is not an argument against impeachment. It is an argument against history. James Madison — the scrivener of the Constitution — intentionally included anti-democratic features in the Constitution to preserve personal liberty from the tyranny of a congressional majority and the tyranny of presidential ignorance. The whole purpose of an independent judiciary, for example, is to be anti-democratic — to preserve the life, liberty and property of the minority from the tyranny of popular laws. And the whole purpose of impeachment is to correct an election after the elected person has demonstrated that he is unfit for office.

The House is operating under rules adopted in 2015, when Republicans ran the House. Schiff is no more secretive about or partisan against the president than my old boss, then-Judiciary chair Rep. Peter Rodino, was toward Nixon or then-Judiciary chair Rep. Henry Hyde was toward Clinton. Both acquired evidence from secret proceedings and both decided to impeach before any public hearings were held.

Impeachment is political, not juridical. Former President Gerald R. Ford was essentially right when he argued that under the Constitution impeachable offenses are whatever a majority of the House says they are — for Nixon, covering up a break-in; for Clinton, lying about consensual sex; for Trump, solicitation, bribery and obstruction.

Whose behavior was arguably the gravest?