Voters have given President Donald Trump the worst ever marks of his presidency, according to a new NBC News-Wall Street Journal poll released on Sunday, which showed ominous signs of voter discontent ahead of the 2018 midterm elections.

Trump's job approval rating hit 38 percent, having tumbled 5 points from September, with 58 percent saying they disapprove of his presidency. His previous low was a 39 percent approval rating in May. The NBC-WSJ poll results largely mirrored the results of a Fox News poll released on Friday, which also showed the president with a 38 percent approval rating amid plummeting support among his Republican base.

The survey results take place against a backdrop of tax reform on Capitol Hill, where both the White House and Congressional Republicans are in desperate need of a legislative win. The high profile failure of Obamacare repeal, coupled with the impending departures of senior GOP leaders, have raised the stakes.

His loss of support also takes place at a time of pitched cultural debate involving professional athletes opting to sit or kneel during the national anthem at games. Last month, the president sparked a firestorm by demanding the NFL require players to stand, or fire them if they don't.

Trump's handling of the aftermath of Hurricane Maria, which resulted in a war of words between the mayor of San Juan and the president, also provoked days of bad press, even as voters appeared to give him a thumbs up for his handling of Hurricanes Harvey and Irma. According to the NBC News poll, the president earned his highest marks on that score.

Separately, however, the death of a soldier in Niger — and Trump's response — also stoked days of controversy and debate about his treatment of gold-star families.

Trump's plummeting approval rating raises questions as to whether he and Congress can ride out voter anger if tax reform efforts should falter.

Independents have become broadly disenchanted with the president, with his support falling from 41 percent in September to 34 percent currently, according to the NBC-WSJ poll. His support among white voters has also fallen below 50 percent, and Trump's ratings among whites without a college degree has also taken a hit.