The accompanying RealClearPolitics chart of trends over the last 30 days illustrates the downward trend in support for Trump — and thus the potential for broader setbacks on Election Day. The chart shows Trump going from a 1 point lead in late May to a 6 point deficit on June 19.

Less publicized trends among key demographic groups are compounding Republican anxiety. Trump’s heaviest losses, according to survey data, are among those voters he most needs to remain competitive: whites and especially white men.

When you compare polls taken between May 22 and 25 (the high point to date for Trump in matchups with Hillary Clinton) with polls published over the last week, you can see how much damage Trump has inflicted on himself. In matchups with Clinton, Trump has experienced double digit declines in support from men, from young voters, from all whites and from white college graduates in particular.

Polls are also showing an increase in the percentage of Republicans who are indicating that they might sit out the 2016 election. The Reuters-Ipsos tracking poll measures how many voters refuse to say whether or how they will vote. Among Republicans, the percentage of these voters has risen since early May from 17.2 percent to 26.6 percent. Among Democrats, the percentage has remained relatively constant, fluctuating between 19 and 21 percent.