The tea party's waning popularity has been closely scrutinized, but a Gallup poll released Thursday demonstrates why the Republican establishment must continue to heed the movement's supporters.

The poll found tea party support at 41 percent among Republicans and GOP-leaning independents, a whopping 20 percentage points lower than in 2010, just after the Republicans' sweeping 2010 election victory. The shift has been mainly due to rising apathy with the movement rather than opposition to it, with a 14-point rise in the Republicans who neither support nor oppose the tea party (or have no opinion). 


But despite their minority status in the party, tea party Republicans continue  to punch above their electoral weight. The Gallup poll also found 43 percent of tea party Republicans have "given quite a lot of thought to midterm elections" this year, compared with just 26 percent of other Republicans. Tea party Republicans were also 17 points more apt to feeling "more enthusiastic about voting this year" than other Republicans (52 vs. 35 percent). 


Those findings align with Pew Research Center polling where more tea party Republicans said they "always vote" in primary elections, by a wide margin. Indeed, both Gallup and Pew polls find that while tea party supporters make up about four in 10 Republicans (and GOP-leaning independents), they account for roughly half of those who are most interested in elections.

A base of highly engaged tea party Republicans is not always enough to win party primaries, as was clear in North Carolina Tuesday where establishment favorite and state House Speaker Thom Tillis fended off two challengers in the Republican primary for U.S. Senate. A dearth of campaign money may have hindered tea party-aligned candidacies, as The Post's Matea Gold reported. Tea party groups reported spending less than$200,000 on yard signs, phone banks and online ads for libertarian Greg Brannon. Pastor Mark Harris had not seen any independent spending on his behalf. By contrast, groups supporting Tillis shoveled nearly $2.5 million in ads and mailers to support him. A Washington Post analysis last month found top national tea party groups have spent a tiny fraction of their money on boosting candidates they've endorsed. 

The Gallup poll was conducted April 24 to 30, among a random national sample of 1,513 U.S. adults on conventional and cellular phones. The error margin is larger among subgroups, including Republicans and GOP-leaning independents.

Peyton M. Craighill contributed to this report.