Businessman Donald Trump surged into the lead for the 2016 Republican presidential nomination, with almost twice the support of his closest rival, just as he ignited a new controversy after making disparaging remarks about Sen. John McCain’s Vietnam War service, according to a new Washington Post-ABC News poll.

Support for Trump fell sharply on the one night that voters were surveyed following those comments. Telephone interviewing for the poll began Thursday, and most calls were completed before the news about the remarks was widely reported.

Although the sample size for the final day was small, the decline was statistically significant. Still, it is difficult to predict what could happen to Trump’s support in the coming days and weeks as the controversy plays out.

Even with the drop in support on the final night of the survey, Trump was the favorite of 24 percent of registered Republicans and Republican-leaning independents. That is the highest percentage and biggest lead recorded by any GOP candidate this year in Post-ABC News polls and marks a sixfold increase in his support since late May, shortly before he formally joined the race.