President Barack Obama at a rally Sunday in Las Vegas. Obama was in Nevada to boost Hillary Clinton's presidential campaign and help Democrats in their bid to retake control of the Senate. AP Photo/John Locher President Barack Obama tore into Republican Senate candidate Joe Heck in a fiery speech in Nevada on Sunday.

The speech marked a departure from Obama's typical campaigning on behalf of Democratic presidential nominee Hillary Clinton, and it serves as a preview of Obama's unprecedented push to help elect down-ballot Democrats ahead of Election Day.

Heck is locked in a hotly contested race with Democrat Catherine Cortez Masto for the seat of the outgoing Senate minority leader, Harry Reid.

Speaking in North Las Vegas, the president blasted Heck for his record on abortion and his views on immigration reform and criminal-justice reform.

He also attempted to link Heck to Republican presidential nominee Donald Trump.

"There's one other difference between the candidates: Catherine never supported Donald Trump," Obama said.

"She never said she had 'high hopes' he would become president. Never said she'd trust his fingers on the nuclear code," Obama added.

Heck rescinded his endorsement for Trump earlier this month after a 2005 recording surfaced of Trump making vulgar comments about women.

"Now that Trump's poll numbers are cratering, suddenly he says, 'No, I'm not supporting him,'" Obama said. "Too late. You don't get credit for that."

Obama criticized Heck's endorsement withdrawal as a political move that didn't reflect how he really felt about the candidate.

"When Donald Trump starts his TV network, I’m sure Joe Heck will be right up on there giving interviews," he said.

At various times in the speech, Obama egged the crowd on with chants of, "What the heck?" and, "Heck no."

He also plugged the campaigns of Jacky Rosen and Ruben Kihuen, two Nevada Democrats running for seats in the House of Representatives.

Democrats are hoping Obama's investment in down-ballot races will give the party an edge in swing districts as the party gears up for the 2018 midterm elections. According to Politico, the list of more than 100 down-ballot, Obama-endorsed candidates reaches as far down the ballot as the Florida House and the North Carolina Supreme Court.

"In a lot of these super-down-ballot races, focus often doesn’t shift down the ballot until very late in the cycle," Carolyn Fiddler of the Democratic Legislative Campaign Committee told Politico. "Given where this campaign has gone from the national level on down, this is going to be a really good way to push a lot of these folks over the line."