- A showdown between the administration

and Democrats in Congress today.

The White House pursuing its policy

of non-compliance withinvestigations on Capitol Hill

is openly defying acongressional subpoena,

and as Jennifer Wishon reports,

it could bring new calls for impeachment.

- On Capitol Hill today, a no-show.

At the request of President Trump,

former White House attorney Don McGahn

said to defy a subpoenato testify before Congress

on the Russia investigation.

McGahn was a key witnessin Mueller's report

and offered, Democrats believe,the most damaging evidence

of obstruction of justiceagainst the President.

The Justice Department issued an opinion,

saying, "Congress may not compel

"the President's senior advisers

"to testify about official duties."

House Judiciary CommitteeChairman Jerry Nadler

is expected to hold McGahn in contempt.

President Trump says theMueller investigation is over.

- Now what happens is theDemocrats want a re-do,

and we've had enough, andthe country's had enough.

- [Jennifer] Democrats are incensed.

- We have a President that isactively trying to cover up

and prevent the American peoplefrom getting to the truth,

and that's not somethingI think we can tolerate.

- [Jennifer] Now, demands forimpeachment among Democrats

are growing louder.

A number of leaders Monday night

privately pressed Speaker Nancy Pelosi

to begin an impeachment inquiry

to attain the documents andtestimony they're seeking.

Speaker Pelosi hasconsistently rejected the idea,

but Chairman Nadler says thePresident isn't above the law.

- Well, the recalcitrance of the President

and his lawless behavior

is making it more and more difficult

to ignore all alternatives,including impeachment.

- [Jennifer] Democratscalling for impeachment

have found a friend inRepublican Congressman,

Justin Amash.

- I think it's a process,

and it's something that should be begun.

- [Jennifer] The President dismisses

his rogue colleague.

- He's been a loser for a long time,

rarely votes for Republicans,

and, you know, personally, I think he's

not much.

- But a federal judge handedDemocrats a victory Monday,

upholding a Congressional subpoena

for the President's financial records

from an accounting firm.

The judge's opinion also makes clear

Congress can investigatethe President's conduct

both before and after he took office.

"It is simply not fathomable

"that a Constitution thatgrants Congress the power

"to remove a President for reasons

"including criminal behavior

"would deny Congress thepower to investigate him,"

the judge writes.

Using history as her guide,

Pelosi fears impeachment proceedings

against the President would be unpopular,

causing voters to rallyto his defense in 2020.

Jennifer Wishon, CBN News, Washington.