Aside from Trump's comments on the 25th Amendment, impeachment and last week's attack on the U.S. Capitol, the president's remarks alongside the border wall were notable in that he spoke -- both in tone and content -- as if he had accepted the end of his presidency was near.

His speech Tuesday reflected an attempt to spend one of his final days in office focused on highlighting what he believes are his accomplishments as president with his signature promise to build a wall among them.

Tump also warned that a "tidal wave" of undocumented immigrants would head toward the United States if his immigration policies are reversed.

"We can't let the next administration even think about taking it down," Trump said, referring to the barrier, although Biden has said he would not dismantle existing barrier -- just stop further construction.

"At this very moment, smugglers and coyotes are preparing to surge the border if our policies are loosened or removed," Trump said. However, Customs and Border Protection chief Mark Morgan told ABC News just a few weeks ago, "the in-flows [of immigrants at the border] have basically slowed to a trickle."

-ABC News' Quinn Owen, Ben Gittleson and John Parkinson

At the top of his remarks in Alamo, Texas, after making brief comments about the strength of the border wall, the president addressed the riot at the Capitol -- remarking that it “has been a difficult year and a difficult election."

“Free speech is under assault like never before,” Trump said -- calling the latest impeachment effort a "hoax" but threatening the efforts to remove him from office could haunt Biden.

“The 25th Amendment is of zero risk to me, but will come back to haunt Joe Biden and the Biden administration," Trump said. "As the expression goes, 'Be careful what you wish for."'

“Millions of our citizens watched last Wednesday as a mob stormed the Capitol and trashed the halls of government. As I have consistently said throughout my administration, we believe in respecting America’s history and traditions -- not tearing them down,” Trump said, reading from a teleprompter.

“We believe in the rule of law, not violence or rioting," he said, going on to describe the pandemic landscape. "This has been a difficult year and a very difficult election. The pandemic has made it a very, very difficult year for our country and virtually every country around the world. Now is the time for our nation to heal -- it is the time for peace and calm."

“Respect for law and law enforcement -- so many are here -- is the foundation of the MAGA agenda, and we are a nation of law and order. That is why we are here today: to talk about what we must do to uphold the rule of law in America and how we must continue to support our law enforcement heroes, which is exactly what you are," Trump said.

At the same time as Trump spoke, acting U.S. Attorney in the District of Columbia Michael Sherwin announced that more serious indictments against some already charged in the violent Capitol siege were imminent and said there were "pipe bombs" found outside the Capitol Wednesday.

Before Tump's remarks, Trump walked slowly to the border wall, lined with American flags. He bantered with border officials speaking as he gazed upon the wall before he approached a plaque and signed it.

-ABC News' John Parkinson and Ben Gittleson

House GOP leadership will not be encouraging members to vote for or against Democrats' impeachment push Wednesday or on a resolution later Tuesday calling on Vice President Mike Pence to invoke the 25th Amendment, according to House leadership aides.

House Leader Kevin McCarthy has already announced that he does not support impeachment, but sources tell ABC News that it’s possible some Republicans may vote to impeach Trump.

On a private House GOP-wide conference call that lasted roughly two hours on Monday evening, GOP Conference Chair Rep. Liz Cheney, the No. 3 Republican in the chamber, told members that they should "vote their conscience" and not as a "political vote," sources familiar confirm.

Cheney has not said if she will support the article of impeachment against Trump, but is not a Trump loyalist and has already shown she is not afraid to split with the party.

-ABC News' Benjamin Siegel and Mariam Khan

The House Rules Committee is in recess for a meeting to tee up a resolution that will be voted on the House floor later Tuesday which seeks to pressure Vice President Mike Pence to invoke the 25th Amendment and remove Trump from office.

While Pence has not indicated publicly what he intends to do, and it's not expected he will take action -- making the resolution's expected passage largely symbolic -- House Democrats will go forth in considering a single article of impeachment Wednesday.

Democrats in the committee rehashed painful, devastating memories to highlight their concerns and rage and exasperation, explaining why they want to make sure Trump is held fully accountable for inciting the riot.

Rep. Jamie Raskin, D-Md,, said he was there with his daughter and son-in-law. His family showed up to support him just one day after burying Raskin's son.

"This is not just a crisis and an emergency. It is a continuing crisis and emergency. It is not over yet," Raskin said. "Can we say that we feel safe being in the hands of this president, with the horror and the threats returning to our nation's Capitol?"

Rep. Norma Torres, D-Calif., described cowering in the House chamber. Hiding under her chair, struggling to put on an escape hood, she called her daughter, telling her, "I'm running for my life" before quickly hanging up.

"Trump incited this attack and there should be no question as to what Vice President Pence needs to do right now," she said. "I heard the shots being fired. I saw the smoke from the tear gas being been deployed. And I watched one officer with no equipment face a raging mob just outside the chamber. We crawled across the entire length of that balcony."

Democrats repeatedly implored Republicans to admit the election was fair and free, and Republicans scolded Democrats for, they say, seeking to divide the country further with a second impeachment.

-ABC News' Mariam Khan

The Delaware Humane Association hosted a virtual party with over 10,000 people to celebrate the first shelter dog moving into the White House.

While Champ and Major won't put their paws in the White House until Wednesday, the association held the fundraiser Sunday to celebrate the history being made: Major was adopted by Biden in March 2018.

"It means everything to us because it shines a light on the work we do," Delaware Humane Association's executive director Patrick Carroll said Sunday during the virtual party. "It shows that shelters are a wonderful place to adopt."

The shelter showed off photos of Major during his stay there in 2018 along with video of him and the president-elect. It also revealed dog "secretaries" which were dogs from its shelter that were selected by fans.

The Delaware Humane Association raised over $100,000, according to its host.

Biden's two German shepherds will also be the first dogs to live in the White House in four years, though Champ is no stranger to Washington. The Biden family brought the dog into their home in 2008 and he resided with them during his two terms as vice president.