Cicatrizatic notices that nearly half of those who participated in the latest formal Reuters-Ipsos presidential preference poll are Democrats while just one-third are Republicans.
Reuters-Ipsos tracks the figures daily. It has done so for a head-to-head match up between Hillary and Trump since May 1. The following graph shows the partisan affiliation of "likely general election voter[s]" through July 8:
Back in May when Trump enjoyed a slight lead in the RCP average, Reuters-Ipsos' Democrat-to-Republican ratio was considerably closer to 1-to-1--and consequently closer to what other surveys have found the country's partisan distribution to be--than it has been for the last several weeks.
That could be a consequence of Republican recalcitrance in the face of Trump's refusal to morph into John Kasich, the tendency for people to identify with whatever party the candidate they intend to vote for is from, a problem with Reuters-Ipsos' sampling methodology (either inadvertently, or, more sinisterly, intentionally), some combination of these things, or something else entirely.
Whatever the explanation, the shift is noteworthy. As the sample has become more heavily Democrat, Hillary's support has correspondingly increased while Trump's has decreased.