What did Donald Trump do today?

He reacted badly to the idea of Congressional oversight.

Today, the House Judiciary Committee issued letters and requests for documents from 81 people and institutions connected to various ongoing investigations.

Trump immediately called the entire thing a "hoax." 

Among the things that the documents sought by the Judiciary Committee are in a position to shed light on are:

• what role now-convicted felon, then-national security advisor Michael Flynn played in connecting the Trump campaign and administration to the Putin regime
• the plans, until recently kept secret and vehemently denied by Trump, to build a "Trump Tower" in Moscow and offer Vladimir Putin a bribe in the form of a free stake in the building
• Trump's attempts to get his attorney general, Jeff Sessions, to un-recuse himself or quit so that Trump could have a free hand to fight the investigation into his ties to Russia
• the specific details of Trump's secret efforts while still president-elect to broker a deal with Putin to drop U.S. sanctions against Russia
• how and how often Trump inflated the supposed value of his assets (to defraud banks he sought loans from) and/or deflated them (to lower his tax bill)
• whether Trump's firing of FBI Director James Comey was (as Trump has openly admitted) an attempt to frustrate an investigation into his ties to Russia, and whether this constitutes obstruction of justice
• how much of the $107 million raised by the Trump Inaugural Committee came from foreign sources, which is illegal
• what Trump's now-convicted campaign manager Paul Manafort and his now-convicted second-in-command Rick Gates did for the Russia-connected Ukrainian politicians that Manafort owed money to
• whether Trump's hush money payments to the women he had sexual affairs with following the birth of his youngest son also violates tax law
• the arrangements made by the publisher of the National Enquirer to "catch and kill"—i.e., pay hush money for—stories about Trump's sexual infidelities
• how many individuals or companies under the control of the Putin regime have done business with the Trump organization, or the businesses that his son-in-law, Jared Kushner, has a stake in
• why the General Services Administration allowed Trump to effectively act as his own government landlord where the federally-owned Old D.C. Post Office property was concerned, in violation of its own rules and the language of the lease contract
• what Trump discussed with Vladimir Putin at meetings where he personally seized the translator's notes and has refused to share details even with his own appointees
• why the Trump campaign shared top-secret voter demographic and turnout data with Russia, which was exactly what Russia needed to tailor its own disinformation campaign on Trump's behalf 
• details on the June 2016 meeting in Trump Tower between Eric Trump, Donald Trump Jr., and Paul Manafort and agents of the Russian government to discuss spying on Hillary Clinton
• how many Russia probe targets discussed pardons with the White House
• how much Trump has monetized the presidency in violation of the Constitution's foreign and domestic emoluments clauses
• if there is any sense in which Trump has removed himself from direct control of the business empire he still receives money from
• the access that convicted Russian spy Maria Butina had to the Trump administration through her relationship with a Trump advisor and her infiltration of the National Rifle Association
• how Matthew Whitaker, generally regarded as severely underqualified for the job, was elevated out of the normal chain of command to the post of acting attorney general
• details on the attempts by mercenary contractor Erik Prince (brother-in-law of Trump's education secretary Betsy DeVos) to set up a secret meeting between Trump transition team members and representatives of several Middle Eastern countries and Russia.
• whether Trump directed his "fixer" Michael Cohen to lie to Congress in support of Trump's political and legal defense to the Russia investigation—which was one of the crimes Cohen was convicted of
• any additional criminal or civil violations committed by Trump's now-shuttered "charity," beyond the ones it has already admitted to
• why the Trump campaign insisted on changing the GOP platform to take a pro-Russia stance on the occupation of Ukraine
• how many Trump campaign and transition officials had contacts with agents of the Putin regime in Russia
• how much Trump and his campaign knew about Wikileaks' plans to disseminate e-mails stolen by Russia from the Democratic National Committee

Trump has not offered any details on why these are all "hoaxes."

Why should I care about this?

• Presidents are not above the law.