Since first threatening a government shutdown last month in his battle with Congress over border wall funding, President Donald Trump has leaned heavily on Twitter to rally support among his followers. So far, the strategy seems to be working. That, however, doesn't bode well for a quick resolution to the standoff. With a partial government shutdown now in its third week, the White House signaled on Sunday that talks to reopen the federal government could produce a deal that sees Trump moving away from his demand that a proposed barrier along the U.S. border with Mexico be a concrete wall.

The possible concession, which comes days after Trump had floated the idea of a barrier of steel rather than a concrete wall, came even as a White House official warned that the shutdown, could "drag on a lot longer." The pledge to build a barrier has made the president a captive of a central campaign promise, which The New York Times says began in 2014 as a way for his aides to get him to remember his hard line on immigration. tweet Speaking to reporters outside the White House on Sunday, Trump repeated his threat that if he is unhappy with negotiations in a few days, he could declare a national emergency and use the military to construct a wall, circumventing Congress. The standoff has left about 800,000 federal employees furloughed or working without pay. The House, now led by Democrats, passed legislation Thursday night to fund the agencies that have been caught in the border wall crossfire. But Trump could still veto the measure even if the Senate acts to approve it. Trump said Sunday he should not have to lower his demand for $5.6 billion in border security funding. As the standoff drags on, Trump has tried to take maximum advantage of the political upheaval to rally support from his followers for his signature 2016 campaign issue. Based on a CNBC review of his wall-related tweets, the effort is paying off.

As the Dec. 22 shutdown loomed, Trump linked President Barack Obama's policy toward Iran with the ongoing battle over border security in a tweet. tweet That post generated more than 60,000 retweets, one of the president's biggest wall-related tweets, according to an analysis of his feed by CNBC, despite inaccuracies. The $150 billion was Iran's own money that had been frozen in financial institutions around the world because of sanctions, the Washington Post reports. Trump then topped it with a Dec. 30 tweet that generated nearly a quarter-million favorites, though the claim that the Obamas built a 10-foot wall around their home has been debunked. tweet

'How do we get him to continue to talk about immigration?'

The subject of a border wall has been a staple of the president's Twitter feed for the last three years. Begun in earnest in the months before he declared his presidential ambitions in June 2015, the pace picked up after his election in November 2016. The number of his followers who support his sentiments with retweets has risen accordingly. While the president's focus on the subject intensified in 2018, the Times reported that talk of the wall began nearly five years ago, as Trump's advisers sought ways to help the candidate focus on immigration. "How do we get him to continue to talk about immigration?" Sam Nunberg, a Trump political advisers, told Roger J. Stone Jr., another adviser, according to the report. "We're going to get him to talk about he's going to build a wall," Nunberg added, according to the Times. The reference to a wall has prevailed as one of Trump's most popular stump lines among his base.