A federal judge in Washington, D.C. declined to block a House subpoena to President Trump's accounting firm, Mazars USA, for his financial records on Monday.

The latest: Trump on Tuesday formally appealed the ruling to the D.C. Circuit Court of Appeals — where the chief judge is Merrick Garland, President Obama's 2016 Supreme Court nominee. Senate Majority Leader Mitch McConnell blocked Garland from ever receiving a confirmation hearing.

What they're saying:

"It is simply not fathomable that a Constitution that grants Congress the power to remove a President for reasons including criminal behavior would deny Congress the power to investigate him for unlawful conduct — past or present — even without formally opening an impeachment inquiry."

— Judge Amit Mehta

"Today's decision is a resounding victory for the rule of law and our Constitutional system of checks and balances. The court recognized the basic, but crucial fact that Congress has authority to conduct investigations as part of our core function under the Constitution ... we urge the President to stop engaging in this unprecedented cover-up and start complying with the law."

— House Oversight Chairman Elijah E. Cummings

The backdrop: Trump's lawyers argued the subpoena was unconstitutional because it wasn't tied to any specific legislation. However, attorneys for the House Oversight Committee said the financial disclosures will serve to improve existing ethics and disclosure laws and give new insight into whether Trump is compliant with the Emoluments Clause of the Constitution.

Between the lines: U.S. District Court Judge Amit Mehta's ruling means Mazars USA must comply with the subpoena for 8 years of Trump's financial records.

Mehta also denied Trump's lawyers' request to stay his order more than the 7 days both sides agreed to for an appeal, ruling the public's interest in "maximizing the effectiveness of the investigatory powers of Congress" was greater than any damage to Trump or his businesses.

Go deeper: Cummings to file subpoena for all of Trump's finances