Sen. Tim Kaine, D-Virginia, revealed on CBS News' "Face the Nation" that he will vote against confirming CIA Director Mike Pompeo as the next secretary of state, becoming the highest-ranking Democratic senator to come out against Pompeo's nomination. President Trump tapped Pompeo to replace Rex Tillerson after his dramatic ouster in March. Pompeo endured more than four hours of questioning on Capitol Hill this week by the Senate Foreign Relations Committee, of which Kaine is a member.

Kaine, who voted to confirm Pompeo to lead the CIA at the beginning of Mr. Trump's presidency, said his support this time around comes down to Pompeo's view of diplomacy.

"We have a president who is anti-diplomacy and I worry that Mike Pompeo has shown the same tendency to oppose diplomacy," Kaine said.

"I don't want a secretary of state who is going to exacerbate the President Trump's tendencies to oppose diplomacy," he added. "You've seen President Trump try to underfund the State Department and USAID, not appoint key ambassadors, tweet out insults about foreign leaders, back the United States out of international agreements and organizations. We do not need a secretary of state who's going to exaggerate those tendencies. We need a secretary of state who is going to stand up for strong diplomacy. I don't believe that's Director Pompeo's inclination."

Kaine also criticized Mr. Trump's decision to launch military strikes against targets in Syria linked to recent chemical attacks without first getting the approval of Congress. The U.S., together with the U.K. and France, targeted three sites in Syria in response to use of suspected chemical weapons on civilians in Douma.

"I hope President Trump will follow the American Constitution. It's very, very clear Congress has the power to declare war and only Congress. So if you're initiating war against a sovereign nation like Syria that hadn't declared war on the United States it's only Congress that can do it. President Trump is not a king. He's a president," said Kaine.

Kaine added, "I'm very troubled that this is a president who seemed to understand what the Constitution required when President Obama was in office. But now he thinks he's a king and he can do whatever he wants without Congress."

He said the administration "had time to come to Congress to seek our permission" but neglected to do so.

The Democrat also pointed to a lack of clear strategy in the region as an issue of concern for Congress.

"We need to defeat ISIS. But we heard different things from the administration. Are we staying there now to topple Assad? To counter Iran? To check Russia? To help the Kurds? To buttress Israel? To rebuild our relationships with Turkey? They haven't laid out a strategy, and military action shouldn't be taken as a one-off. It should be taken as part of a strategy," said Kaine.

Shortly after the reports of the coalition effort on Friday, Kaine released a statement condemning Mr. Trump's decision to launch an airstrike without congressional approval as "illegal" and "reckless."

"Assad must face consequences for his war crimes, but presidents cannot initiate military action when there isn't an imminent threat to American lives. Today, it's a strike on Syria. What's going to stop him from bombing Iran or North Korea next? The last thing Congress should be doing is giving this President a blank check to wage war against anyone, anywhere. We need to put clear limits in place before he starts another war, and I'm working to do just that," Kaine added.

On Sunday, Kaine suggested the president could use similar arguments to justify military action in other global hot spots.

"What's to stop him from starting a bombing campaign against Iran or North Korea or some other nation and saying, 'Well, I think it's in the national interest?'" Kaine questioned.