In a recent letter on behalf of the president to the House committees on impeachment, the president's counsel Pat A. Cipollone wrote:
I write on behalf of President Donald J. Trump in response to your numerous, legally unsupported demands made as part of what you have labeled contrary to the Constitution of the United States and all past bipartisan precedent-as an "impeachment inquiry." As you know, you have designed and implemented your inquiry in a manner that violates fundamental fairness and constitutionally mandated due process.
For example, you have denied the President the right to cross-examine witnesses, to call witnesses, to receive transcripts of testimony, to have access to evidence, to have counsel present, and many other basic rights guaranteed to all Americans. You have conducted your proceedings in secret. You have violated civil liberties and the separation of powers by threatening Executive Branch officials, claiming that you will seek to punish those who exercise fundamental constitutional rights and prerogatives. All of this violates the Constitution, the rule of law, and every past precedent. Never before in our history has the House of Representatives-under the control of either political party-taken the American people down the dangerous path you seem determined to pursue.
The last paragraph names the following:
the right to cross-examine witnesses
[the right] to call witnesses
[the right] to receive transcripts of testimony
[the right] to have access to evidence
[the right] to have counsel present
To me, these seem like rights a defendant would have in a trial in most countries with an established legal system. Impeachment inquiries, however, are different from criminal trials in that they are aimed at collecting evidence like a police investigation might for the purpose of a future criminal trial.
In the impeachment procedure, the current step is not similar to a trial but the stage during which evidence is collected and witnesses are interviewed. Given the timing of the letter and the letter calling the inquiry "constitutionally illegitimate proceedings" it seems the White House is claiming that these rights should be available now.
Hence my question:
To what extent were the five aforementioned rights actually granted to defendants (then presidents) in past impeachment inquiries (i.e. the investigative phase of the impeachment process preceding the vote in the House of Representatives on articles of impeachment)?