Washington (CNN) On the same day that a Democratic-led US House committee voted for articles of impeachment against President Donald Trump , the Supreme Court made its own momentous decision to intervene in Trump's effort to keep his tax returns and other financial records secret.

The justices agreed to resolve in spring 2020 if a sitting president should be immune from any criminal proceeding, whether related to conduct before taking office or even -- to use Trump's famed example -- shooting someone on Fifth Avenue in New York . The high court also said it would determine the oversight authority of Congress in paired disputes arising from attempts by House Democrats to obtain Trump's financial documents.

The eventual decisions would help define the high court in the Trump era, especially as Chief Justice John Roberts has tried to carefully navigate Trump-related litigation and regularly declares that the justices are above politics.

Roberts, who was appointed by President George W. Bush in 2005, has tried to shield the judiciary from the polarization in Washington, stepping up his efforts after the contentious confirmations of Trump appointees Neil Gorsuch and Brett Kavanaugh. Last year, Roberts admonished Trump and said judges should not be labeled as "Obama judges" or "Trump judges," but rather as neutral decision-makers.

That notion might be especially challenged with these new cases and rulings that would come by the end of June, when the justices traditionally recess for the summer, and just as the 2020 presidential election is intensifying.

The Supreme Court is already a flashpoint in the presidential election campaign. The nine justices are deeply divided among ideological lines. The five Republican-appointed conservatives often comprise the majority, with the four Democratic-appointed liberals dissenting.

Depending on who wins in 2020, the next president could further entrench that divide, or, alternatively, upset it. Three of the justices are in their 70s and 80s: Ruth Bader Ginsburg , who will be 87 in 2020; Stephen Breyer who will be 82; and Clarence Thomas who will be 72.

Even before Friday's move, the Supreme Court's calendar was loaded with important social dilemmas. It is poised to rule in the next year on new state abortion regulations, LGBT rights in the workplace, and the legal status of hundreds of thousands of undocumented immigrants.

Now, all nine will be thrust into a high-stakes battle between the executive branch and Congress, as well as the longstanding controversy regarding Trump's refusal to make public his tax returns.

None of the three cases involve Trump's official actions as President. They trace to his business dealings before taking office, such as possibly directing "hush money" to women who have claimed they had affairs with him.

In all three cases the justices are scheduled to hear in March, lower court judges grounded their decisions against Trump in decades-old Supreme Court precedent that would allow a President to be subpoenaed or sued. So, any reversal would be startling.

Running out the clock

The acceptance of a case for review does not determine the outcome. Nonetheless, the Supreme Court's brief order on Friday signals that at least four justices -- the number required to grant a case a hearing -- believe Trump has a legitimate claim in his assertions that a president should be protected from state investigation while in office and similarly shielded from broad congressional oversight.

On a practical level, even though Trump lost the early rounds on all these disputes, he has nonetheless prevailed in running the clock and fighting subpoenas that were issued months ago.

In urging the justices not to hear Trump's effort to block a subpoena to his longtime accountants Mazars USA, lawyers for the US House noted that House members are elected for two-year terms, so further delays would "prevent the people's representatives from carrying out their constitutional duties in the limited remaining time they possess."

Trump's lawyers countered that if the high court failed to intervene, elected officials would use their subpoena authority to try to find "dirt" on political rivals: "Intrusive subpoenas into personal lives of Presidents will become our new normal in times of divided government -- no matter which party is in power."

Can a president be investigated while in office?

By the time the justices take up these cases, any House impeachment and Senate trial would be over.

The House's inquiry arose from Trump's dealings with Ukraine. These new cases involve Trump's refusal to make public tax returns and other financial records dating back about a decade.

In the New York grand jury case, testing a subpoena sought by Manhattan District Attorney Cy Vance, Trump's lawyers have asserted that he is absolutely immune from any criminal investigation -- not only from indictment, which had been common understanding -- while he holds office.

The lower court ruling in this case, Trump v. Vance, was narrow. "(A)fter reviewing historical and legal precedent," the New York-based appeals court said, "we conclude only that presidential immunity does not bar the enforcement of a state grand jury subpoena directing a third party to produce non-privileged material, even when the subject matter under investigation pertains to the President."

A Supreme Court decision could sweep more expansively, just as any ruling related to House investigations could break ground on the separation of powers.

On issues from immigration to impeachment, Trump has suggested he could turn to the Supreme Court to rescue him and uphold his administration's policies. It also was not lost on Trump that he was helped in his 2016 campaign by a pending vacancy on high court.