Mrs Clinton's double-digit lead, which she has held over the past several months, has vanished - and with it, apparently, Democrats' dreams of a transformational 2016 victory that would leave Republicans wandering the wilderness for a generation.
What happened? A closer look at those poll numbers offers some clarity.
Remember the #NeverTrump movement? No one in the Republican Party seems to. While certain pundits (Bill Kristol) and politicians (Mitt Romney) continue to tilt at the independent-conservative-candidate windmill, the rank and file of the party appear to be falling in line behind their presumptive nominee.
As for the party establishment, most prominent officeholders seem to either be backing Mr Trump or trying their best to disappear into the scenery. Even Senator John McCain, whose war record was belittled by Mr Trump last summer, has said he'll support the party nominee.
While there still seems to be significant interest in a third-party candidate - 44% of respondents told Washington Post pollsters that they wanted another choice - every passing day makes such a development less likely.
Republicans are deciding that Mr Trump - warts and all - is their guy. The scene last week, where Mr Trump - who once backed an assault weapons ban - received a hero's welcome and an unusually early endorsement from the National Rifle Association, only drove that point home.