President Barack Obama is struggling to overcome widespread pessimism about the economy and deep frustration with Washington, notching the lowest job-approval ratings of his presidency in a new Wall Street Journal/NBC News poll.

The results suggest Mr. Obama could weigh on fellow Democrats in midterm elections this fall, particularly in the conservative states that will play a large role in deciding whether his party retains its Senate majority.

Mr. Obama's job approval ticked down to 41% in March from 43% in January, marking a new low. Some 54% disapproved of the job he is doing, matching a previous high from December, when the botched rollout of his signature health law played prominently in the news. The latest survey also showed the lowest-ever approval in Journal/NBC polling for Mr. Obama's handling of foreign policy.

(See five takeaways from Obama's approval rating.)

The findings come amid dissatisfaction with all elected leaders in Washington and low regard for the Republican Party. Roughly a quarter of those polled view the GOP positively, with 45% harboring negative views, weaker numbers than for the Democratic Party.