President Trump is responding to his weakening political position by trying ever-harder to display strength.

The display is not convincing.

In today's extraordinarily-fractious, on-camera Oval Office session with congressional Democratic leaders, Trump highlighted his own vulnerability. First, he repeated his false claim in early morning tweets that his long-sought U.S-Mexico border wall has largely been built, with the Pentagon poised to complete it even if Congress won't provide financing.

That telegraphed his expectation that lawmakers won't include wall funding in the year-end spending bill needed to keep government open. Anticipating defeat undercuts Republican leaders who've demanded that funding on Trump's behalf.

Trump hobbled his own cause further by trying to strike an unyielding pose. Baited by incoming House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer, he blurted out precisely what skilled budget adversaries have learned not to say for fear of drawing political blame.

"I am proud to shut down the government for border security," Trump declared.

Since some border-state Republicans themselves oppose the wall, that's a risky line to draw even in the waning days of an all-GOP Congress. It gets riskier when hostile Democrats take over the House next month, backed by polls showing that most Americans oppose a border wall.

The president's haphazard concession emboldened Democrats and dispirited fellow Republicans at the same time. "Trump won't work to preserve the leverage they need to exact concessions or negotiate," lamented Kevin Madden, a former House GOP aide.

Trump seeks to paper over deteriorating conditions on other fronts as well.

After publicly announcing the departure of beleaguered White House chief of staff John Kelly, Trump told reporters he'd announce a successor in a day or two. Then, once his chosen replacement quit the administration instead of accepting the offer, Trump insisted on Twitter that "many, over ten (people), are vying for and wanting" the job.

Potential aides remain hesitant in large part because of darkening legal clouds. Trump's first National Security Adviser, campaign chairman and personal lawyer have all confessed to felonies.

In recent days prosecutors have obtained the cooperation of a now-jailed Russian who interacted with Trump at a 2015 campaign event. They've laid out in more detail the lies of his associates who now await sentencing.

"Totally clears the president. Thank you!" Trump tweeted about those filings last Friday. In fact, prosecutors asserted that candidate Trump had directed the commission of two campaign finance felonies.

Evidence compiled by special counsel Robert Mueller and the U.S. Attorney for the Southern District of New York has increased the likelihood that a Democratic House next year will initiate impeachment proceedings. Former Rep. Tom Davis, a one-time member of the House GOP leadership, told me "they'll likely get a few Republicans to join them."

Even before Mueller has laid out all his findings, Republicans lost their House majority to a 40-seat Democratic sweep. If political conditions deteriorate further, Davis added, it will be "uphill but not impossible" that Senate Democrats could amass enough Republican support to convict Trump on impeachment charges and remove him from office.

In August, Trump warned such a Democratic effort would hit Americans in their pocketbooks. "If I ever got impeached," he told Fox News, "I think the market would crash."