Clinton Looks to Widen Lead Over Sanders With Wins in Kentucky, Oregon Wins for Clinton tonight would not be enough for her to secure the nomination.

 -- Even though Donald Trump and Hillary Clinton are gearing up for the general election, they still need to amass the required number of delegates to secure their respective nominations.

Clinton is trying to prevent losses in Oregon and Kentucky tonight to Sen. Bernie Sanders. She's been working hard to secure a win in Kentucky, campaigning there on Monday alongside Alison Lundergan Grimes, a former Senate candidate and the current Kentucky secretary of state. Clinton won the Bluegrass State primary in 2008 against then-Sen. Barack Obama.

Kentucky and Oregon offer Clinton and Sanders opportunities to add significantly to their delegate counts. There are 61 delegates up for grabs in Kentucky and 74 in Oregon. (In Kentucky, 55 of the delegates are pledged, and six are superdelegates; in Oregon, there are 61 pledged delegates and 13 superdelegates.) But with little polling available, it's tough to tell where the Kentucky race stands.

Sanders, speaking to reporters today in Puerto Rico, said his team is focused on making sure Democrats head to the polls tonight.

"I feel about Oregon and Kentucky the way I usually feel, and that is if there’s a large voter turnout, I think we’ll win. Kentucky and Oregon pose the usual problems for us in the sense that they are closed primaries. Independents are not allowed to vote," he said.

Even if Clinton sweeps today's primaries, she would still be short of winning the nomination. She needs an additional 143 delegates to reach the required 2,383 to secure the nomination. Sanders currently has 1,473 delegates to Clinton's 2,240.

The chances of a sweep are slim, given that both Democratic contests allocate delegates proportionally for candidates who cross the 15 percent threshold.

Former President Bill Clinton is campaigning on behalf of his wife in Puerto Rico before the island's contest on June 5.

On the Republican side, Trump could take home all of Oregon's 28 delegates, but that still would not be enough for him to clinch the nomination. The likely Republican presidential nominee needs 1,237 delegates to secure the nomination, and ABC News estimates that he currently has 1,143.