Washington - Public support for President Donald Trump is dropping, a poll showed on Sunday, as he faces multiple setbacks over his stalled agenda and efforts to repeal and replace Obamacare.Nearly six months since he took office, Trump is facing a declining approval rating that has dropped from 42% in April to 36%, according to a Washington Post-ABC News poll of 1 001 adults. Similarly, his disapproval rating has jumped five points to 58%.A total of 48% of respondents said they "disapprove strongly" of the president's performance in office - a low threshold never reached by ex-presidents Bill Clinton and Barack Obama, both Democrats, and only reached once by George W. Bush, during his second term.And 48% also see American global leadership weakening since Trump entered the White House, while 27% said it is stronger. Most respondents (66%) said they do not or only somewhat trust Trump in negotiating with foreign leaders, especially with Russian President Vladimir Putin (also 66%). Of those, 48% said they do not trust Trump "at all" in negotiations with Putin.Opinions over Russian meddling in the 2016 presidential election and whether the Trump campaign colluded with Moscow - a subject of multiple investigations - divided sharply along partisan lines.Only 33% of Republicans polled said Russia tried to influence the election, compared with 80 percent of Democrats. Overall, 60$ of all American adults said Russia tried to tilt the elections, a slight increase from 56% in April.Just seven percent of Republicans said the Trump campaign intentionally helped Russian efforts, compared with 65% of Democrats.In recent days, it was revealed that Trump's eldest son Donald Trump Jr. and two other senior campaign officials met in June 2016 with a Russian lawyer in hopes of receiving damaging information about Democratic rival Hillary Clinton.A total of 63% of respondents said the meeting was inappropriate, while just 26% said it was appropriate. However, nearly half (48%) of all Republicans polled said the meeting was in fact appropriate.While 52% of respondents said Trump has tried to interfere with investigations into whether Moscow tried to sway the elections, that was a drop from 56% in June.The poll, conducted July 10-13, has a margin of error of plus or minus 3.5 percentage points.