The unfolding Ukraine scandal that is one of the several impeachable crimes being investigated by Congress ranks among the most whiplash inducing Trump scandals to date. A deluge of evidence has flowed from the military, aides, ambassadors, and other figures involved in Ukraine either through official diplomatic channels or Trump's backchannel with his personal lawyer, Rudy Giuliani. Each testimony and indictment is quickly followed by lies and misdirection from the White House. It has been very difficult to keep track of the events while running a business, so I want to pass the mic and highlight the best summary of events so far, thanks to Reddit user poppinKREAM.
The Significance of a Phone Call Between President Trump and Ukrainian President Zelensky
In a phone call on July 25 2019 with newly elected Ukrainian President Zelensky, President Trump attempted to solicit the support of a foreign government and may be in violation of Federal Campaign Finance Laws.  When President Zelensky asked about military aid to combat Russia, Trump immediately segued the conversation into requesting an investigation against one of his political opponents. President Trump repeatedly made requests including opening up an investigation into former Vice-President Joe Biden and his role in the firing of a Ukrainian prosecutor that Trump claims was supposedly unfairly shut down by Biden because he supposedly feared his son was being investigated.
This is a complete mischaracterization of events. Following Ukraine's revolution and Russia's annexation of Crimea, Ukrainian President Poroshenko was dealing with corruption scandals. Prosecutor General Viktor Shokin was a discredited individual who was leading an investigation into corruption. The corruption was staggering, for example following assistance from the International Monetary Fund a $1.8 billion loan to help the Ukrainian banking system disappeared offshore in accounts owned by a Ukrainian Oligarch.  At one point Shokin fired prosecutors who were working on corruption cases against corrupt officials.  Following pressure from Western Allies and the Obama administration the Ukrainian parliament overwhelmingly voted to fire Prosecutor General Viktor Shokin. The decision was celebrated by Western Allies that were providing financial support to Ukraine including the European Union to defend themselves from Russia.  Moreover, in a recent interview former Ukrainian Prosecutor General Yuri Lutsenko debunked President Trump's conspiracy that Biden forced the firing of Shokin to protect his son, Hunter Biden, who had been working in Ukraine. Prosecutor General Lutsenko stated that “from the perspective of Ukrainian legislation, he did not violate anything,” and added “Hunter Biden cannot be responsible for violations of the management of Burisma that took place two years before his arrival.” 
Days before his conversation with Ukrainian leader Zelensky the Trump administration suddenly froze aid allocated to Ukraine. 
The White House has attempted to mislead the public by claiming that aid was frozen due to corruption, however NPR obtained a letter from the Pentagon that certified Ukraine had taken action to decrease corruption 2 months before President Trump blocked aid.  Furthermore, the Trump administration had tried to cut billions of dollars to programs aimed at fighting corruption globally including millions in cuts to anti-corruption programs in Ukraine. 
A month before this phone call in June the Pentagon announced plans to provide $250 million to Ukraine in security cooperation funds for things such as training and equipment in an attempt to build the capacity of Ukraine's armed forces following Russia's illegal invasion of Ukraine.  The State Department announced plans to provide $141 million in aid. 
Why are the United States and Western allies sending aid to Ukraine? In 1994 former Soviet Union member states including Ukraine signed the Budapest Memorandum. It was a diplomatic memorandum under which Ukraine removed all Soviet-era nuclear weapons and signed the Nuclear Nonproliferation Treaty. In return for these concessions the former Soviet state consecrated the sovereignty and territorial integrity of Ukraine as an independent state by applying the principles in a Cold War era treaty signed by 35 states including the Soviet Union. Russia violated this agreement in 2014 when they invaded Ukraine. 
Following the phone call a whistleblower from DNI filed a complaint that stated President Trump was "using the power of his office to solicit interference from a foreign country in the US 2020 election," characterizing the conduct as a "serious or flagrant problem, abuse, or violation of law". President Trump has been attempting to cover all of this up.  A Trump appointed Inspector General detailed his concerns in letters where he stated that the whistleblower complaint being kept from Congress was both urgent and “relates to one of the most important and significant of the (Director of National Intelligence)’s responsibilities to the American people.” 
The U.S. Ambassador to the EU and major Trump campaign donor Gordon Sondland told Congressional investigators that this was a quid pro quo deal.  Furthermore, top U.S. diplomat Bill Taylor testified to Congress that President Trump extorted Ukrainian President Zelensky by withholding $400 million in military aid. President Trump wanted President Zelensky to publicly act out a fake news script about opening up an investigation into Biden. 
Several associates of the President's personal attorney have been arrested and charged by the Justice Department for violating campaign finance laws. Giuliani's associates Lev Parnas and Igor Fruman were engaged in a scheme to funnel foreign money into American political campaigns so they could buy influence in the U.S.. Furthermore, Giuliani was working with Parnas and Fruman in Ukraine trying to land lucrative bussiness deals between President Trump's allies and one of the largest Ukrainian state owned gas companies. This occurred a few months prior to President Trump withholding military aid while pushing the newly elected Ukrainian President to investigate President Trump's domestic political rival.
Associates working closely with Giuliani were arrested and charged by the Justice Department as they tried to influence American politics. 
Lev Parnas, Igor Fruman, David Correia, and Andrey Kukushkin, the defendants, conspired to circumvent the federal laws against foreign influence by engaging in a scheme to funnel foreign money to candidates for federal and state office so that the defendants could buy potential influence with candidates, campaigns, and the candidates' governments. The defendants concealed the scheme from candidates, campaigns, federal regulators, and the public by entering into secret agreements, laundering foreign money through bank accounts in the names of limited liability corporations, and through the use of straw donors (also known as "conduits" or "straw contributors") who purported to make legal campaign contributions in their own names, rather than in the name of the true source of the funds.
Months before the now infamous phone call between President Trump and newly elected President Zelenksy, Guiliani was in Ukraine trying to find dirt on Biden. He was working with his business associates Lev Parnas and Igor Fruman.  During the same period in which they were helping Giuliani in Ukraine, Parnas and Fruman were pursuing a lucrative deal with a Ukrainian state owned oil company known as Naftogaz. They were part of a group trying to install new management at the top of Ukraine's massive oil company. 
What have we learned since Giuliani's associates were arrested? Parnas and Fruman were working on behalf of Pro-Russian Ukrainian oligarch Dmitry Firtash who is currently detained in Vienna fighting extradition to the U.S. on bribery and racketeering charges.
Two of Giuliani's associates were trying to fly out of the U.S. and possibly to Vienna, Austria. 
Mr. Giuliani said Thursday that Messrs. Parnas and Fruman were headed to Vienna, Austria, on Wednesday evening for reasons related to their business. He said the two men had also left the country about two weeks ago and had traveled to Vienna between three and six times in the last two months. He said he had been scheduled to meet with the two when they were to return to Washington within days.
Around the same time his associates were arrested at Dulles airport, Giuliani told a reporter that he was about to fly out to Vienna. 
A Pro-Russian Ukrainian oligarch is detained in Vienna. Dmitry Firtash is fighting extradition to the U.S. on bribery and racketeering charges.  Curiously, Giuliani's indicted associate was working on behalf of Firtash. 
While President Trump has attempted to distance himself from Giuliani's indicted associate Lev Parnas, we have learned that Parnas attended a private 2016 election night party. 
We have learned that President Trump removed a career state department official from her post following complaints from Giuliani and his associates.  Former Republican congressman Pete Sessions began to attack Ambassador Marie Yovanovitch on conservative media outlets. From recent indictments we have learned that Pete Sessions was being funded by Giuliani's associates Parnas and Furman. These associates have been indicted by the DoJ for trying to bribe American politicians. Ambassador Marie Yovanovitch was a career public servant that supported anti-corruption initiatives in Ukraine, however she was removed from her position while Giuliani's associates as well as President Trump tried to influence the Ukrainian government. 
19) Wall Street Journal - Two Giuliani Associates Who Helped Him on Ukraine Charged With Campaign-Finance Violations: Prosecutors say Lev Parnas and Igor Fruman were part of a conspiracy to funnel foreign money into U.S. elections