It has been said that the voting bloc President Trump cares about most — or maybe even cares only about — is his base. And while Trump won the support of certain voting blocs generally viewed as part of his base, such as white evangelicals and older Americans, few groups are viewed as being more synonymous with Trump’s base than white working-class voters.

But even though this group gives Trump higher marks than most -- only 37 percent of Americans approve of Trump job’s performance, according to the latest CNN poll, white working class voters’s support for the president is declining. CNN reported:

“The increase in disapproval for the President comes primarily among whites without college degrees, 45% of whom approve and 47% disapprove, marking the first time his approval rating with this group has been underwater in CNN polling since February 2018. In December, his approval rating with whites who have not received a four-year degree stood at 54%, with 39% disapproving.”

While Trump easily won white working-class voters in the 2016 presidential election, a lot has changed since then. The president has found himself in more controversies related to his financial dealings, high turnover among White House staffers and his relationship with Russian power players. It is perhaps these concerns that are playing a part in causing white working-class voters to express declining support for the president.

Unsurprisingly, white working-class voters remain supportive of Trump’s proposed border wall, but they are more likely than not to blame the president for the government shutdown — a situation that came as a result of failed negotiations with Democrats to get a border wall. It will be telling to see whether white working-class voters will continue backing Trump’s hard-line immigration policies even if that means prolonging the government shutdown that has greatly inconvenienced many of their lives.

While most federal workers affected by the shutdown are in the Washington area, a Post analysis found that as a percentage of all workers, federal employees affected by the shutdown are as common in Montana and Alaska — states with significant percentages of white working-class voters — as in Maryland. In fact, four federal government employees from Texas and West Virginia — states Trump won — are suing the Trump administration, claiming that the shutdown amounts to involuntary servitude and thus a violation of the 13th Amendment.

If the shutdown continues and the public’s view on the matter doesn’t change, Trump’s approval ratings could continue to drop with a group of Americans who helped send him to the White House. And if Trump does not do anything to reverse his decline in popularity with white working-class voters, it could be difficult for him to win a reelection campaign launched with the slogan “Promises Kept.” Because for many Trump supporters, including the white working-class voters who supported him, failing to deliver on a border wall and bringing jobs back to the United States to increase the chances of economic gains being felt by the white working class is the exact opposite of keeping one’s campaign promises.