Americans feel disconnected from both the Democratic and Republican parties and helpless about the presidential election, a new poll finds.

Just 12 percent of Republicans and 25 percent of Democrats said their respective parties are very responsive to ordinary voters, according to a poll conducted by the Associated Press and the NORC Center for Public Affairs Research.

The poll also found that only small minorities of Americans have much trust in political parties, with 15 percent of Americans reporting a great deal of confidence in the Democratic Party and just 8 percent saying the same about the GOP.

Many are crediting Americans' widespread skepticism of political institutions for the unexpected popularity of anti-establishment presidential candidates Donald Trump and Bernie Sanders, who have both characterized themselves as outsiders and promised to shake up the status quo if elected president.

Trump in particular has spent his campaign sharply criticizing his party's leaders — a tactic that helped invigorate his voting base to turn out at the polls and ultimately handed him the Republican presidential nomination.

And despite efforts by both parties to inspire voters, hopelessness is the prevailing attitude about the presidential race. Sixty percent of Republicans and 53 percent of Democrats feel helpless about the 2016 election, including two-thirds of voters under age 30.

The poll was conducted among 1,060 adults May 12-15 with a 4.1 percentage point margin of error.

Another AP poll released late last week similarly found that almost four out of 10 Americans have "hardly any" trust in the U.S. political system.