CBS News Chief White House correspondent Major Garrett reported Tuesday that House Democrats in their articles of impeachment are "walking back away" from allegations against President Trump, including bribery and extortion, upon which they were recently focused.

"Why do you think that the Democrats have backed away from a word that they used quite prominently not so long ago, 'bribery'?" asked CBS News anchor Anthony Mason just before top House Democrats unveiled the impeachment articles. "And also extortion. What is the reason behind that?

"Well, they clearly don't believe they have the evidence to make that case stick," Garrett replied. "Bribery, extortion, those were words that had great power and force about a week ago, maybe two weeks ago absent from this docket, if you will, of impeachment articles.

"Something else is conspicuously missing: obstruction of justice," Garrett continued.

He later added: "Obstructing justice was part and parcel of the Clinton and Nixon impeachment procedures. Not so this time. Why? Because House Democrats have, by any historical measure, accelerated this impeachment process, so they've not gone through what other impeachment processes have, court challenges over disputed documents or witnesses."

"If a White House defies a court order to comply for a subpoena you can propound an article of obstruction," he added. "But Democrats don't want to wait for the court procedures, in some cases haven't even engaged them to test this question in court. They've left with obstruction of Congress, which is a smaller sounding, and in the history of impeachment, less enforceable, or less, let's say, strident accusation against the White House.

"In both cases, House Democrats are in full public view walking back away from some of the things they were alleging quite loudly two weeks ago," Garrett concluded.

Democrats earlier Tuesday unveiled two articles of impeachment against the president, including abuse of power and obstruction of Congress.

House Intelligence Committee Chairman Adam Schiff (D-Calif.) said on Tuesday that Congress had to move quickly to prevent Trump from cheating in the next election.

"The argument 'Why don't you just wait?' amounts to this: 'Why don't you just let him cheat in one more election?' " Schiff said. "'Why not let him cheat just one more time? Why not let him have foreign help just one more time?'" That is what that argument amounts to," Schiff told reporters.

The House Judiciary Committee is expected to vote on the articles this week before the process moves to the full House. A simple majority vote is needed in the Democrat-controlled House to move to the Senate.

A two-thirds vote, however, would be needed to convict the president in the Republican-controlled Senate.