Photo

Hillary Clinton holds a wide lead over Donald J. Trump in a new national poll that came out shortly after the Manhattan businessman became the presumptive Republican nominee.

The CNN/ORC poll, released Wednesday morning, shows Mrs. Clinton with 54 percent of respondents’ support, compared with 41 percent for Mr. Trump, a lead that is one percentage point above her showing in a similar survey in March.

The poll suggested that Mrs. Clinton’s support is driven heavily by aversion to a Trump candidacy: 51 percent of her supporters say their backing comes more from opposition to Mr. Trump than from a preference for the Democratic candidate. But the same is true for those who said they supported Mr. Trump: 57 percent said their backing was driven by an opposition to Mrs. Clinton.

The poll shows that Mrs. Clinton’s rival, Senator Bernie Sanders of Vermont, would hold an even wider lead over Mr. Trump than Mrs. Clinton: In a hypothetical matchup, Mr. Sanders would beat Mr. Trump by 16 percentage points, the poll suggested.

Mr. Sanders has seized on his strong performance against Mr. Trump in polls as a main argument for keeping his candidacy alive despite Mrs. Clinton’s lead in delegates.

Both Mr. Trump and Mrs. Clinton hope to clinch their parties’ nominations by getting the required majority of their parties’ delegates by the last round of state contests, on June 7.

The CNN/ORC poll of 1,001 adults had a margin of sampling error of 3.5 percentage points.