(CNN) Two days before televised impeachment hearings begin, Donald Trump's allies are peddling a smokescreen of conspiracy theories and distractions, hoping to sow confusion over the case against him.

Trump himself aggressively squelched the one defense that could ease the political pain of moderate Republican lawmakers. He warned that it would be unacceptable for any Republican to argue his phone call with Ukrainian President Volodymyr Zelensky was inappropriate but did not meet the constitutional standards for removal.

"Republicans, don't be led into the fools trap of saying it was not perfect, but is not impeachable. No, it is much stronger than that. NOTHING WAS DONE WRONG!" Trump tweeted Sunday

Fierce political exchanges over the weekend offered a preview of how Republicans and Democrats will joust for advantage when the televised hearings get underway on Wednesday.

Republicans will seek to deflect, take the investigation down political rabbit holes and create a spectacle with an eye to Trump's conservative media cheerleaders and his supporters. They will also seek to confuse the case with details and factually dubious arguments designed to complicate it in the eyes of Americans watching the proceedings.

Democrats will battle to keep their simple abuse of power case from being corrupted by Republican attacks. They will try to turn the public against Trump by using witnesses drawn from political and military service -- like the current top US diplomat in Ukraine Bill Taylor on Wednesday and the ousted US ambassador to the country, Marie Yovanovitch, on Friday.

"They are going to hear immensely patriotic, beautifully articulate people telling the story of a President who ... extorted a vulnerable country by holding up military aid," Democratic Rep. Jim Himes of Connecticut said on NBC's "Meet the Press."

Trump supporters also took to Sunday talk shows. Their arguments reflect the reality that for Trump partisans the next few weeks will not necessarily be about finding the truth about what happened in his off-the-books foreign policy with Ukraine.

In a war for public opinion, they will instead seek to construct plausible narratives that can shield the President and themselves from any wider political backlash.

The President's friends are keen to talk about anything -- other than the currently easy-to-understand facts of the case that Democrats have been building through witness testimony.

The case against Trump

Trump stands accused of abusing his power by trying to coerce Ukraine to open an investigation into a domestic political opponent -- former Vice President Joe Biden and his son Hunter. There is no evidence of wrongdoing by either Biden. Multiple witnesses have now testified that they believe he demanded a quid pro quo from Ukraine while holding up $400 million in military aid as it battled Russia.

But several Republicans argued Sunday that the President was merely worried about corruption in Kiev -- an argument that challenges credibility since it concerns a topic that Trump has rarely shown any interest in pursuing elsewhere in the world.

"The quid pro quo, in my judgment, is a red herring," said Sen. John Kennedy, a Louisiana Republican, on CBS' "Face the Nation." "Here are the two possible scenarios. Number one, the President asked for an investigation of a political rival. Number two, the President asked for an investigation of possible corruption by someone who happens to be a political rival."

"The latter would be in the national interest. The former would be in the President's parochial interests and would be over the line," Kennedy said, constructing an alternative narrative that offers Trump and GOP supporters a way out of a box.

Wisconsin GOP Sen. Ron Johnson also claimed on CNN's "State of the Union" that the President was concerned about good governance in Kiev, rather than seeking personal political advantage.

"When you're going to provide hundreds of millions of taxpayer dollars into a system, you want to make sure it isn't corrupt," Johnson told CNN's Jake Tapper.

"I never heard the President say, 'I want to dig up dirt on 2020 opponents.'"

Kentucky Republican Sen. Rand Paul made a novel argument -- that Trump's offense was merely to reach for the same kind of leverage that everyone else in Washington uses.

"I would make the argument that every politician in Washington, other than me, virtually, is trying to manipulate Ukraine to their purposes," he said.

"They're all doing it. They're all trying to manipulate Ukraine to get some kind of investigation -- either to end an investigation or start an investigation."

Paul's comments blur the issue. Biden's pressure on Ukraine during the Obama administration -- in common with the European Union and international organizations -- was motivated by a desire to improve investigations of corruption, not to shut them down.

Witness depositions appear to suggest that pressure by Trump and his personal attorney Rudy Giuliani was motivated by a desire to investigate Biden -- a potential 2020 rival -- and his son, who served on the board of a Ukrainian gas company.

Republicans are also expected to argue that while Democrats have built up evidence from foreign policy officials, they have yet to prove that Trump or those closest to him directly ordered the withholding of aid or asked for political concessions. The argument is perhaps their strongest opening to undermine the Democratic impeachment case.

Still, the refusal of the White House to make available witnesses like Giuliani, who was acting for Trump in Ukraine, and acting chief of staff Mick Mulvaney allows Democrats to argue that the White House has something to hide.

The White House transcript of Trump's July 25 call with Zelensky shows that he asked his counterpart for a "favor" and requested he look into Biden and his son. And in a stunning moment in a White House briefing, Mulvaney effectively confirmed that a quid pro quo took place.

Republicans want the House hearings to probe Hunter Biden and the whistleblower

Several Republicans demanded testimony in impeachment hearings from Hunter Biden and called for a whistleblower who first raised the alarm about Ukraine to testify in public.

"I consider any impeachment in the House that doesn't allow us to know who the whistleblower is to be invalid, because without the whistleblower complaint, we wouldn't be talking about any of this," Senate Judiciary Chairman Lindsey Graham said on Fox.

"I also see the need for Hunter Biden to be called to adequately defend the President. And if you don't do those two things, it's a complete joke," the South Carolina Republican said.

House Intelligence Chairman Adam Schiff, a California Democrat, has already argued that exposing the identity of the whistleblower is unnecessary since the person's complaint has been confirmed by witness testimony.

"In light of the President's threats, the individual's appearance before us would only place their personal safety at grave risk," Schiff wrote in a Saturday letter to Rep. Devin Nunes, the ranking Republican on the Intelligence Committee, that was obtained by CNN's Manu Raju.

Democrats argue that calling for Hunter Biden to testify is irrelevant to the impeachment case -- since it is a constitutional proceeding designed solely to judge whether the President abused his power. And such a move would also in effect create the political investigation -- in Congress no less -- into the Bidens that Trump sought to get the Ukrainians to initiate.

Trump's Capitol Hill allies over the weekend lodged a list of witness requests apparently designed to cause havoc in the hearing room -- or a talking point when Democrats who have the power of the majority reject them.

They requested Hunter Biden and the whistleblower, but also Nellie Ohr, a former contractor for intelligence firm Fusion GPS, and Alexandra Chalupa, a former Democratic National Committee staffer.

Those two names suggest a Republican focus on unsubstantiated claims that Ukraine and not Russia interfered with the 2016 presidential election -- despite voluminous evidence and indictments of Moscow-linked suspects compiled by former special counsel Robert Mueller.