Ukrainian Prime Minister Arseniy Yatsenyuk says Russian President Vladimir Putin is bent on slicing off more territory from neighboring lands in an attempt to rebuild a romanticized ideal of the Soviet Union.

In an interview with Meet the Press that will air Sunday, Yatsenyuk says Putin has his sights set on eastern Ukraine, where pro-Russian separatists have in the past two weeks taken over buildings and sparred with security forces.

"President Putin has a dream to restore the Soviet Union," he says, "and every day he goes further and further, and God knows where is the final destination."

The remark comes days after Putin referred to eastern Ukraine as "new Russia" and warned that he could send troops to the region to protect ethnic Russians. And it comes as Ukrainian troops are engaged in a deadly clash to dislodge entrenched separatists from the area. A shootout at a checkpoint on Sunday left one dead and hospitalized others.

The U.S. government to some degree shares Yatsenyuk's concern. Putin infamously said in a 2005 speech that the collapse of the Soviet Union was the "greatest geopolitical catastrophe of the century." --Jon Terbush

NASA announced Monday that its Hubble Space Telescope has found more evidence of "water plumes" on the surface of Jupiter's moon, Europa. If the plumes, which NASA describes as water vapor "erupting off" Europa's surface, do in fact exist, it would offer scientists hoping to study Europa's massive subsurface ocean a way to study the water without having to drill through miles of hard ice to get there.

Europa's ocean has two times the amount of water Earth's oceans have, making it "one of the most promising places that could potentially harbor life in the solar system," Geoff Yoder, acting associate administrator for NASA's Science Mission Directorate in Washington, said in a press release.

The latest findings mark the second time NASA has reported spotting water plumes on Europa's surface; in November and December 2012, scientists noticed water vapor near the moon's southern pole. NASA is planning to launch two missions to Europa sometime in the next decade, Ars Technica reported.

For more on the plumes — including what they may look like — watch NASA's video, below. Becca Stanek

Not even Glenn Beck — the conservative radio host who reportedly spent $500,000 on travel stumping for Ted Cruz during the Republican primaries — is ready to let the Texas senator off the hook for endorsing Donald Trump. In an interview on Beck's radio show Monday, Beck repeatedly tried to get Cruz to explain his decision to vote for Trump — despite the fact that during the Republican National Convention, Cruz used his speech to advise Americans to "vote your conscience" rather than to endorse the GOP nominee.

At first Cruz tried to paint his convention speech as a way to "lay out a path to uniting Republicans," explaining that this election is "a binary choice" and Hillary Clinton isn't the choice to make. But Beck wasn't ready to let Cruz get away with once again refusing to say whether Trump is fit to be president. "So a man, who you cannot come on [the show] and say, 'Yes, Glenn, he is fit to be president of the United States,' I still am encouraged by you to abandon my principles and vote [for him] because it's a binary choice?" Beck asked.

By the end of the nearly 20-minute conversation, Beck had to admit he "strongly" disagreed with Cruz — and he was reportedly even more candid after he hung up the phone. "I think I have to apologize, and say, maybe, perhaps, those of you who said Ted Cruz is calculating and a smarmy politician, I think I may have to slightly agree with you and apologize for saying, 'No, he wasn't,'" Beck said, as reported by The Daily Beast. Then, Beck apparently twisted the knife, reportedly admitting that maybe, just maybe, he should've supported Sen. Marco Rubio (R-Fla.) in the primary instead.

Listen to the entire interview, below. Becca Stanek

The weekend's intense rain in the Midwest may finally be subsiding, but in Cedar Rapids, Iowa, floodwaters are continuing to rise. As of Monday morning, the Cedar River crested at 16 feet, which constitutes a "major flood event," Time reported. By Tuesday morning, the river is expected to crest at 23 feet, which NBC News noted would put the water "11 feet above flood stage." The waters are rushing down to Cedar Rapids from Wisconsin, where two people died last week because of flooding.

The last time Iowa waters rose this high was in 2008; that flood, which The Des Moines Register called the "worst in the city's history," resulted in an estimated $10 billion in damages.

Residents of Cedar Rapids and in other areas of Iowa have been advised to evacuate, while curfews have also been installed in some parts of the state. CNN reported Iowa Gov. Terry Branstad (R) and Wisconsin Gov. Scott Walker (R) have "each declared disaster emergencies for 13 counties, freeing up state resources to respond to the flooding." Becca Stanek

Tonight is a big night for the swath of voters who still haven't decided whether they're team Donald Trump or team Hillary Clinton. A Reuters/Ipsos poll released Monday, the day of the first presidential debate between Trump and Clinton, revealed that of the 50 percent of likely voters who are using the presidential debates to guide their decision this November, 10 percent still don't even prefer one candidate over another.

But for all those voters who are hopeful the debates will bring some much-needed clarity, 39 percent of respondents were already resigned to the fact the debates "will not help" them choose a candidate, Reuters reported. Another 11 percent weren't sure how the debates will shape their decisions.

The debate will be moderated by NBC's Lester Holt at New York's Hofstra University. Reuters reported it is expected to draw "a Super Bowl-sized audience of 100 million Americans."

The Reuters/Ipsos poll was conducted among 1,337 likely voters across all 50 states, and has a margin of error of plus or minus 3 percentage points. Becca Stanek

Hillary Clinton and Donald Trump will finally face off Monday night, in the first of three presidential debates. For Trump, preparing for the debate has meant getting used to working on a timer and practicing staying even-keeled and optimistic; Clinton, meanwhile, has been holding marathon run-throughs and honing her mental discipline.

But Trump's former campaign manager-cum-CNN commentator Corey Lewandowski thinks Clinton could do without all the formal practice and instead just focus on one thing: becoming human. "What Hillary Clinton has to do here is she has to become human, and I mean that in a good way," Lewandowski said Monday on a CNN panel, per Politico. "There's no question about [the fact that she knows the issues], but what she doesn't have is that compassion that people can see."

Lewandowski's critique of Clinton as coming off wooden is not new, and is a claim that has dogged the Democratic nominee throughout her political life. In a lengthy report for The Washington Post published Friday, writer Marc Fisher explored Clinton's problems with being perceived as even "likable enough," as Barack Obama said memorably in 2008 — to the point where she believed the press would publish even the most bombastic of rumors about her:

Lewandowski — who is still receiving severance from the Trump campaign while being paid by CNN for his work — also said Monday that he believed Trump would exceed expectations at Monday night's debate. Read more of his comments at Politico, or read Fisher's full story on Clinton's authenticity problem at The Washington Post. Kimberly Alters

If Election Day got bumped up to Sept. 26, FiveThirtyEight predicts Donald Trump would claim a huge victory. In Monday's now-cast election predictor, released hours ahead of the first presidential debate between Trump and Hillary Clinton, the Republican presidential nominee's chances of winning were nearly 10 points higher than Clinton's, 54.9 percent to 45.1 percent.

Of course, a lot can change over the course of 43 days. But the trends over the last couple months in this particular FiveThirtyEight forecast have shown Trump steadily gaining ground and Clinton steadily losing it. After Trump briefly pulled ahead in late July, Clinton's lead peaked on Aug. 8, when she had a 96.4 percent chance of winning and Trump had just a 3.6 percent chance. Since then, it's been a slow but steady downhill slide for Clinton.

Moreover, while Clinton has consistently led since June in FiveThirtyEight's polls-plus predictor, which takes polls, historical data, and the economy into the equation, she now holds her slimmest lead yet in that measure, too: In the polls-plus forecast, Clinton's chances of winning on Nov. 8 are 51.9 percent, while Trump's are 48.1 percent. Becca Stanek

And the hits just keep on coming.

Just days after 21-year league veteran Kevin Garnett announced his retirement from the NBA — joining fellow icons Kobe Bryant and Tim Duncan in hanging 'em up after the 2015-2016 season — Garnett's erstwhile teammate Paul Pierce announced Monday via The Players' Tribune that the 2016-2017 season would be his last.

"I'm at peace with retiring, but I've got one more ride left," Pierce wrote. “With the [Los Angeles] Clippers, in the city where I grew up, I feel like I have that opportunity … to win a championship."

Pierce played his first 15 seasons with the Boston Celtics, joining forces with sharp-shooter Ray Allen and the emotional, defense-anchoring Garnett to win a championship in 2008. He then spent one season each with the Brooklyn Nets and the Washington Wizards before joining the Clippers in the summer of 2015. He is a 10-time All-Star team selection and was also the 2008 NBA Finals MVP. Below, a look at some of his best career plays. Kimberly Alters