Paul Callan is a CNN legal analyst, a former New York homicide prosecutor and of counsel to the New York law firm of Edelman & Edelman PC , focusing on wrongful conviction and civil rights cases. Follow him on Twitter @paulcallan . The opinions expressed in this commentary are his own. View more opinion on CNN.

(CNN) Prosecutors in serious criminal cases like to start strong and finish strong to bring home a guilty verdict. They have to grab the attention of the jury before defense attorneys sully the water. Former federal prosecutor and Harvard Law grad, House Intelligence Committee Chair Adam Schiff, successfully executed the first part of this strategy, making a compelling case against President Donald Trump in a carefully crafted and smoothly delivered opening statement. He successfully brushed aside an assortment of "points of order" and other parliamentary procedure stalling tactics which were employed by the minority Republicans to disrupt the flow of the proceedings.

He also hinted at a surprise. The real case against President Trump may rest on "abuse of power" as charged in prior impeachment cases. This relates to the President's defiance of congressional subpoenas and his willful refusal to cooperate with lawful congressional investigations. Such actions may violate the Constitution's requirement of checks and balances between the three branches of government. After all, the founding fathers had just fought the Revolutionary War to curb tyranny and none of them wanted a tyrannical president.

The abuse charge provides a good backup impeachment theory if the Ukraine allegations fail to resonate in the Republican-majority Senate. Republicans should fear that a tyrannical Trump may someday be followed by an equally tyrannical Democrat. Or maybe they enjoy being slapped around by the executive branch of government.

Mr. Schiff also followed another rule employed by respected trial attorneys. They never "overpromise." Schiff accomplished this task, delivering a non-inflammatory but carefully constructed explanation of how the President allegedly abused his power by using $400 million of American military aid to Ukraine as his own personal weapon in an attempt to destroy his political opponent, Joe Biden.

Schiff then proceeded to swear in two witnesses who would testify together. They were US chargé d'affaires in Ukraine, Ambassador Bill Taylor, and Deputy Assistant Secretary of State for European and Eurasian Affairs George Kent. Throughout the hearing, Kent remained relatively silent while Taylor, a gray-haired, distinguished diplomat right out of central casting did the heavy lifting.

Taylor explained in somber but sometimes colorful detail the bizarre backdoor channel to Ukraine designed by Trump and his minister -- without any portfolio whatsoever -- Rudy Giuliani. The purpose of this back channel was to use Giuliani and a pair of Trump appointees rather than the so-called "Deep State" professional diplomats who Mr. Trump distrusts, to convey an ominous warning to Ukrainian President Volodymyr Zelensky . The message in substance: "No Biden investigation, no $400 million in military aid." The announcement would be made in an interview on Trump's most vilified network, CNN.

Taylor's testimony revealed that in visits to Ukraine's Donbass front he was told that at least one or two Ukrainians were dying every day in a hot war with Russia for control of the Ukrainian coal production region. American aid was desperately needed, and delay meant death to Ukraine's soldiers. The conclusion any reasonable person would draw from such testimony is that the President's threats and the actual withholding of aid was aiding and abetting Russia. It was also causing the death of brave Ukrainians, American allies defending their homeland. All of this so Trump can beat Biden in the next presidential election. In some respects, it actually sounds far worse than Richard Nixon throwing a few dollars to the Watergate burglars and then elaborately covering it up. No one died as a result of Nixon's theoretically impeachable offenses.

In contrast, testimony on Day 1 of the House impeachment hearing suggested that American professional diplomats feared that Trump's delay in the disbursement of Ukraine's $400 million in military aid could telegraph a lack of American commitment, creating the real potential to cost the lives of Ukrainian soldiers by encouraging Russian aggression.

Unfortunately for the Democrats, their case against the President began to fade as Republicans successfully muddied the water throughout the afternoon. They posed questions suggesting that any presidential effort to steer the Ukrainian criminal investigations were legitimate efforts to expose what they claimed was Ukrainian sabotage of the 2016 American presidential election, citing a theory that has been debunked. (Even a former Trump official has acknowledged it had no merit .)

The Steele Dossier raised its ugly head, as did the prosecution of Paul Manafort. The Republican questions were designed to remind Americans of the perfectly legal and abundantly funded Mueller/Russia investigation which haunted the first half of the Trump presidency.

And why was Hunter Biden reportedly being paid $50,000 a month by Ukraine's largest energy company, Burisma, when he didn't even reside in Ukraine or have an extensive background in the energy business? And why was his father constantly traveling to Ukraine and demanding the firing of a prosecutor investigating Burisma and maybe Hunter? Congressional questions require no supporting evidence, and none was provided. In fact, no evidence has surfaced of wrongdoing by Joe or Hunter Biden in this matter. The Republican point: If it was proper to spend millions of dollars to investigate Russian efforts to influence the American election, how can it be an impeachable offense to compel Ukrainian cooperation in an investigation of the very same subject. And if the investigations link to Biden corruption, all the better.

Those carefully prepared and distinguished "central casting" diplomats Taylor and Kent started to look flustered and confused since they knew nothing about the unrelated topics that Republicans like Jim Jordan threw angrily into the conspiracy questions pot.

Any real American courtroom would overrule his wandering conspiracy-themed questions as not relevant to the direct testimony of the witnesses or even within their knowledge. Courts also prohibit witness speculation. But this is Congress on television and not a court of law, and as congressional cross examination goes, Jordan did a great job in establishing that virtually all the evidence produced by Taylor and Kent was classic hearsay. Like Trump, he would be entertaining on"The Apprentice," though as potential competition to Trump, he would soon be fired.

There was one new testimonial nugget revealed at the first hearing. Taylor revealed that Tim Morrison, then a National Security Council official, allegedly learned of a conversation between the US Ambassador to the European Union Gordon Sondland and the President, in which Trump insisted that Zelensky publicly announce that he was beginning investigations of "Biden and 2016 election interference."

Get our free weekly newsletter Sign up for CNN Opinion's new newsletter. Join us on Twitter and Facebook

This snippet is hearsay, and though Jordan and his Republican colleagues were happy to remind Schiff earlier in the day that the "Federal Rules of Evidence" do not apply to congressional hearings, this time they wanted the hearsay thrown out.

Having no rules of evidence in place permitted Republicans to pontificate conspiracy theories in confusing speeches posing as questions. Such repeated conduct would lead to a contempt citation in any American courtroom. But the Republicans favor strict enforcement of the hearsay rule only when it helps their case. This enables them to say the information about a direct connection to Trump is "inadmissible" hearsay.