 -- Amid President Donald Trump’s continued insistence that “nobody really knows for sure” who interfered in the 2016 presidential election, Sen. James Lankford took a much clearer stance when appearing on ABC News’ “Powerhouse Politics” podcast.

“It is incredibly clear that Russia was trying to interfere in our election,” the Oklahoma Republican said. “There is no question on that, by any means, that Russia was trying to engage -- try to destabilize our democracy.”

Although Lankford invoked the oft-repeated Republican line that Russian hacking did not actually change votes, he highlighted the need to “apply pain” to deter the Russians from further cyberattacks.

Using an analogy from the Olympics, he elaborated, "When it was clear that the Russians were doping their athletes in Sochi, the U.S. Olympic Committee responded by kicking their athletes out of the 2016 Olympics. They faced a real consequence for that, that was clear and was connected."

He continued: "So my issue now is: what is the clear pain that Russia will experience based on their actions? Because I don't think they change the behavior until they actually have experienced some sort of pain."

So what would this pain look like in the context of international cybersecurity policy? Lankford explained that it would have two components. The first, he said, is continued sanctions against Russia, and notably, a sanctions package recently passed the U.S. Senate overwhelmingly, 98-2.

The second component is a “cyber doctrine,” he said.

“It's something we worked with the Obama administration for years on,” Lankford said. “To have a clear policy that can be put out, that if any nation, whether it's North Korea, Iran, China, Russia, whoever it may be -- if they try to interfere in any of our infrastructure, or our systems through a cyberattack, we have a structured response that they know: ‘If you do this, then this is how we respond.’”

Trump assigns blame to former President Barack Obama for not taking stronger action against Russia during the election cycle. Lankford underscored the need for a more proactive approach, saying, “There is unfinished business from the Obama administration, that there was never a clear statement about the ‘if, then’ of cyber warfare.”

At any rate, anticipation runs high as Trump is set to meet Russian President Vladimir Putin Friday at the G-20 summit in Hamburg, Germany. But Lankford said that it was not critical for Trump to raise the issue of Russian hacking during the meeting. “I think it should be something that's on a staff level, at a minimum. Whether the two principals -- with Putin and Trump -- have to be able to have that conversation face to face, I don't think that's essential.” North Korea and Syria, according to Lankford, are more pressing topics for the heads of state.

Finally, when asked when the Senate Intelligence Committee’s ongoing investigation on Russian interference and possible collusion would reach its conclusions, Lankford said, “I would assume it's by the end of the year, but it's still months away.”