Washington (CNN) President Donald Trump has lashed out again at Democrats' impeachment push, tweeting a rapid-fire series of arguments in his own defense over three tweets Tuesday morning.

Trump has made these same claims (or very close) before. But since public impeachment hearings are beginning on Wednesday, it's worth breaking down his case.

Let's go point by point:

"Why is such a focus put on 2nd and 3rd hand witnesses..."

Various witnesses who have testified in the impeachment inquiry have had firsthand knowledge of various components of the Trump administration's dealings with Ukraine.

For example, witnesses Lt. Col. Alexander Vindman and Tim Morrison of the White House's National Security Council both listened to Trump's July phone call with Ukrainian President Volodymyr Zelensky; so did witness Jennifer Williams , an aide to Vice President Mike Pence.

The former ambassador to Ukraine, Marie Yovanovitch, testified about what she had been directly told about why Trump was abruptly removing her from her post.

Trump's ambassador to the European Union, Gordon Sondland, testified about his own comments to Ukrainian officials about how US military aid would not "likely" be issued until Ukraine declared that it was conducting an investigation related to Joe Biden. (Sondland described this proposed declaration as an "anti-corruption statement.") Among other firsthand testimony, Trump's current top diplomat in Ukraine, Bill Taylor , testified about his own concerns about the role Trump's personal lawyer, Rudy Giuliani, was playing in relations with Ukraine.

"...many of whom are Never Trumpers..."

There is no evidence that "many" of the impeachment witnesses are "Never Trumpers" under the traditional definition of the term: longtime Republicans who refuse to support Trump.

Though we can't be certain of the private political beliefs of people who have testified, the witnesses have included Trump's own appointees; administration aides; and career diplomats with no history of public support of or opposition to political candidates.

Trump appears to be trying to redefine the term "Never Trumper" so that it applies to anyone who criticizes his actions.

"...or whose lawyers are Never Trumpers..."

Trump has a better case here. After Trump was elected, Taylor's lawyer John Bellinger joined "Checks and Balances," a group of conservative lawyers formed to speak out against Trump. Mark Zaid , a lawyer for the whistleblower, has represented both Democrats and Republicans and sued both Democratic and Republican administrations, but he has been open about his opposition to Trump: "Anti-Trump. Worst presidential choice in modern history. Not a repub or dem issue," he wrote on Twitter in 2017.

"...all you have to do is read the phone call (transcript) with the Ukrainian President and see first hand?"

The document the White House released says on its first page that it is "not a verbatim transcript." Vindman has testified that some details were omitted from the document.

Regardless, Trump's frequent contention that the phone call was "perfect" is highly questionable. Contrary to Trump's repeated assertions , the call document shows that the whistleblower's allegations about the call were highly accurate: Trump sought to get Zelensky to investigate Biden, to investigate a debunked conspiracy theory about Democratic computer servers, and to speak to Giuliani and Attorney General William Barr.

The whistleblower described these requests as pressure, which Trump is entitled to dispute. But the underlying facts are not in dispute.

"He (Zelensky) and others also stated that there was 'no pressure' put on him to investigate Sleepy Joe Biden..."

Zelensky has indeed said that he did not feel pressured by Trump. "Nobody pushed me," he told reporters while sitting beside Trump at a meeting at the United Nations in September. (When CNN's Clarissa Ward asked Zelensky the next week if he felt pressure from Trump to investigate the Bidens to get the aid, Zelensky responded indirectly, saying , "I'd like to tell you that I never feel pressure. I have lots of people who'd like to put pressure on me here and abroad. But I'm the president of an independent Ukraine and I'd like to think and my action suggests, no one can put pressure on me.")

CNN , the The New York Times and others have described a difficult internal debate within Zelensky's team about how to handle Trump's push for an announcement of investigations.

"...as President, I have an 'obligation' to look into corruption, and Biden's actions, on tape, about firing the prosecutor...are certainly looking very corrupt (to put it mildly!) to me."

There is no evidence of Biden acting corruptly.

Trump appeared to be referring to a 2018 video of Biden telling the story of how he used a threat to deny Ukraine a $1 billion loan guarantee to successfully pressure Ukrainian leaders to fire a chief prosecutor, Viktor Shokin, who was widely seen by the US government, its European allies and Ukrainian activists to be ineffective in fighting corruption.

"He was executing U.S. policy at the time and what was widely understood internationally to be the right policy," Trump's former special envoy to Ukraine, Kurt Volker, testified

All that aside, nothing would have obligated Trump to push a foreign leader to investigate an American political rival or announce an investigation into that person, nor to link such an investigation or announcement to the execution of American foreign policy.

"His son's taking millions of dollars, with no knowledge or talent, from a Ukrainian energy company, and more millions taken from China, and now reports of other companies and countries also giving him big money..."

Joe Biden's son, Hunter Biden, did make significant money from his role on the board of directors of Ukrainian natural gas company Burisma; he has not denied reports that his salary was $50,000 per month.

Hunter Biden, a lawyer who had worked in the Commerce Department and served on the Amtrak board, acknowledged in October that he would "probably not" have been invited to join the Burisma board if his father were not Joe Biden; he said he had done "nothing wrong at all" but had used "poor judgment" in getting involved in such a "swamp."

It is not clear how much money Hunter Biden has earned from China. Trump has repeatedly claimed that Hunter Biden pocketed $1.5 billion, but he has not presented evidence for this claim; Hunter Biden told ABC that it has "no basis in fact," adding, "No one ever paid me $1.5 billion, and if they had, I would not be doing this interview right now."

A lawyer for Hunter Biden, George Mesires, says the investment company in which his client has held a 10% stake was capitalized with a total of about $4.2 million in Chinese money at today's exchange rates, "not $1.5 billion." (Even this investment -- made when Biden was a member of the company board, not a part-owner -- was not a direct payment to him, and Mesires says Biden has not made a profit from his investment.)

There is no evidence of illegal behavior by Hunter Biden.

"Both Bidens should be forced to testify in this No Due Process Scam!"

Trump didn't specify here what he was referring to, but he has previously alleged that he is being denied due process because his lawyers are not being permitted to participate in the impeachment hearings.

Trump is entitled to make this subjective argument. The Constitution, however, does not mandate the House of Representatives to allow the President's lawyers to participate in impeachment proceedings. The Senate holds a trial after the House votes to impeach; the House is not obligated to treat its own process as if it were a trial.

Democrats are beginning their public hearings in the House Intelligence Committee. Their rules will permit Trump lawyers to submit evidence and ask questions of witnesses once the process moves to the House Judiciary Committee, which will make the decision about whether to draw up articles of impeachment.