Democratic presumptive nominee Hillary Clinton on Tuesday won the last presidential primary of the season in Washington DC. Her victory with 79% of the votes came with a clear majority over rival Bernie Sanders, who won the remaining 21% of votes.

Clinton is set to meet with the Vermont senator, hoping for his support ahead of the Democratic Party convention in Philadelphia next month. “We’re going to have a wide-ranging conversation because we share a lot of the same goals…I very much am looking forward to having his support in this campaign because Donald Trump poses a serious threat to our nation,” she said.

While Sanders vowed to do all in his power to stop the presumptive Republican nominee’s entry into the White House, he refused to endorse Clinton. The Vermont senator said that at the meeting, he will be able to determine how committed she is to the policy issues he has focused on during his 13-month campaign, The Associated Press reported.

By last week, Clinton had secured enough delegates to become the party’s nominee for the United States presidential election in November. A count of all the delegates she won in the primaries and caucuses across the country and a survey of superdelegates, who have the power to support any candidate, had indicated that Clinton had the overall support of the required 2,383 delegates she needed for the nomination. She was also endorsed by President Barack Obama on June 10.