(ABC News) -- Senate Majority Leader Mitch McConnell, R-Ky., dismissed as "ridiculous" the idea among some Democrats of forcing a government shutdown if Congress doesn't resolve the issue of young undocumented immigrants facing possible deportation with the ending of the Obama-era DACA program.
"There's not going to be a government shutdown. It's just not going to happen," the Senate Republican leader told ABC News Chief Anchor George Stephanopoulos on "This Week" Sunday.
Congress needs to pass a spending bill by Dec. 8 to keep the government funded and avoid a shutdown.
Stephanopoulos asked McConnell about a growing number of Democrats' "saying they're not going to agree to a deal to keep the government open" unless Congress addresses the situation of about 800,000 young immigrants covered by DACA, the Deferred Action for Childhood Arrivals program which the Trump administration is ending.
"That's a ridiculous idea," the Senate leader said. "There is no crisis. The president has given us until March to address the issue of undocumented children who came into the country ... through no choice of their own and are in a kind of difficult spot."
"I don't think the Democrats would be very smart to say they want to shut down the government over a nonemergency that we can address anytime between now and March," he added. "That's a very untenable position."
McConnell also addressed Senate Republicans' major victory in passing a massive tax overhaul early Saturday morning.
The majority leader said he's "very optimistic" the Senate and House will reach agreement on combining their two tax bills.
"We'll be able to get to an agreement in conference. I'm very optimistic about it," he said. "We think this will make a big difference in getting our economy moving again and providing jobs and opportunity for the American people."
Analysis from the nonpartisan Joint Tax Committee of the Senate plan says the Senate tax plan will add about $1 trillion to the deficit over the next decade.
But McConnell said he is confident the legislation will boost the economy enough to raise tax revenues, offsetting the bill's tax cuts.
"Let me point out there are a whole lot of economists who think that it will pay for itself. And let me tell you how that is done. The economy would have to grow 0.4 percent over the next 10 years to fill this gap that you're referring to. That is not a dramatic improvement. We think you're going to get a lot more growth than that," McConnell said.
"I'm confident this is not only revenue neutral to the government, but actually it's very likely to be a revenue producer," he said.