Donald Trump, the GOP nominee for president, vaulted to a four point lead over Hillary Clinton just prior to the Democratic National Convention this week in Philadelphia, according to a Morning Consult poll of 2,502 registered voters.

Trump now leads Clinton 44 percent to 40 percent, says the poll, which was conducted from July 22 through July 24. It has an error margin of 2 percent.

The New York City developer’s lead is a sizable swing from the past week, when Clinton was clinging to a 2-point lead, wrote Kyle Dropp, Morning Consult’s executive director of polling, and Cameron Easley, the firm’s managing editor.

“Trump has been on a positive trend since the Department of Justice determined that there wasn’t enough evidence to prosecute Clinton for her use of a private email server for official business while serving in the Obama administration,” Dopp and Easley said. “The Republican National Convention came in for criticism from much of the major media outlets … [but the] new Morning Consult survey indicates the typical post-convention bump that a party tends to receive following their gathering.”

In a pre-GOP Convention Morning Consult poll conducted July 14 to 16, Clinton was the choice of 41 percent, virtually the same as in the new poll.

However, Trump’s support moved upward from 39 percent. He gained as the “undecided” voters shrank from 20 percent pre-convention to 16 percent post-convention.

“More than four in 10, 43 percent, of voters said the convention gave them a more favorable impression of the Republican Party, whereas three in 10, 31 percent, said it gave them a less favorable view of the Democratic Party,” they said.

“The convention itself received a fair amount of attention from the public. More than half of voters (53 percent) said they listened to a lot or some of the convention,” they said.

“Almost half, 48 percent, rated Trump’s speech as good or excellent, which is essentially tied with the speech given by his daughter, Ivanka Trump, but higher than his running mate, Mike Pence, or RNC Chairman Reince Priebus,” they said.

The poll also showed a consolidation of the base among Republicans, they said. “Eighty-five percent of Republicans in the new poll said they would vote for Trump, compared with just less than eight in 10 Republicans, 79 percent, from the week before.”