Julian Zelizer, a history and public affairs professor at Princeton University and a CNN political analyst, is the author of " The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society ." He's co-host of the "Politics & Polls" podcast. The opinions expressed in this commentary are his own.

(CNN) Unless something goes terribly wrong, Congress is about to send President Trump a major piece of legislation that imposes tough sanctions against Russia for interfering in the 2016 election, its ongoing human rights violations, its annexation of Crimea and military operations in Eastern Ukraine.

In a striking rebuke to Trump, the Republican-led Congress is including in the legislation provisions that constrain the President if he wants to lift the sanctions on his own. The bill also imposes sanctions on North Korea and Iran. At some level, on Russia, many Republicans are saying through the legislation that they have had enough with the President's bromance with Vladimir Putin.

The administration has sent mixed signals about what the President intends to do if Congress sends him the bill this week but it appears he may well sign it. "The administration is supportive of being tough on Russia," said White House press secretary Sarah Huckabee Sanders , "particularly in putting these sanctions in place. The original piece of legislation was poorly written, but we were able to work with the House and Senate, and the administration is happy with the ability to do that and make those changes that were necessary, and we support where the legislation is now." Given that the legislation has overwhelming support in both the House and Senate, a presidential veto would likely be overridden.

Of course, on the very same day, in classic Trumponian fashion, his new communications director, Anthony Scaramucci, raised doubts about the reports of the US intelligence community about the Russian intervention in the election. "There's a lot of disinformation out there," he told Jake Tapper, citing an unnamed source who told him that if the Russians had done this there would never be evidence. The source, he soon admitted, was President Trump.

Jumping into the fray, the President provided a fireside tweet when he added on Sunday: "As the phony Russia Witch Hunt continues, two groups are laughing at this excuse for a lost election taking hold, Democrats and Russians!"

A different tune on 'voter fraud'

The mixed signals coming from the President are quite striking compared to the way that POTUS has tackled another election-related issue, voter fraud. Unlike the Russian intervention, the overwhelming consensus of experts is that America does not have a major problem with voter fraud . Almost every major study on the subject has failed to turn up evidence that there are a significant number of ballots cast by people who aren't actually eligible to vote.

The Brennan Center , for instance, reported that the rates of voter fraud, most of which resulted from clerical errors and bad data matching practices, were about .00003% and .00025%.

The Washington Post in 2014 only turned up 31 credible cases of vote fraud out of 1 billion ballots over 14 years (2000-2014).

Indeed, in his book "Give Us the Ballot," Ari Berman has shown how for decades, allegations of voter fraud have been used as a political justification for voting restrictions that tend to disenfranchise groups who tend to vote Democratic.

Despite the evidence, President Trump has been using his bully pulpit to talk about the problem of voting fraud since he took office, going so far as to say in an outlandish claim that it was only because of fraud that he lost so badly in the popular vote.

"In addition to winning the Electoral College in a landslide," he tweeted on November 27, "I won the popular vote if you deduct the millions of people who voted illegally." In fact, he lost the popular vote to Hillary Clinton by a margin of more than 2.8 million votes . He has made false allegations of mass voting fraud repeatedly and with total certainty.

More importantly, he has now established a Presidential Commission on Election Integrity, whose vice chairman is Kris Kobach, who has been a leading advocate of voter restriction legislation. The commission could well produce recommendations to institute more restrictive measures.

Talk about fake news. In 1965 , President Johnson signed legislation that guaranteed the federal government would protect the voting rights of all Americans. Today, we have a president who seems intent on using the power of the federal government to move in the exact opposite direction now that the Supreme Court has sharply limited implementation of the Voting Rights Act

Russia trying to undermine democracy

With Russia, the preponderance of evidence from key intelligence agencies, legislators in both political parties, and voting experts confirms that the Russians intervened in our election through a mass disinformation campaign and stealing Democratic National Committee emails through hacking. "There is no dissent," said Director of National Intelligence Dan Coats. In the United States, in France and in Germany the Russians are "trying to undermine Western democracy," he told the Aspen conference.

Yet President Trump and many of his advisers refuse to acknowledge what we know. In a puzzling pattern, the President has refused to be strong, resolute and consistent in saying what happened and, more importantly, moving forward with some kind of policy recommendation to prevent this in the future. His biggest initiative to date was the proposal to set up a joint cybersecurity program with the Russians themselves, an idea he quickly abandoned! This is a little bit like the owners of a bank asking the people who robbed them to work as the guards in the future.

Trump adviser Kellyanne Conway told Brian Stelter that Russia's intervention into the election is "not a big story" and accused the "mainstream news media" of having this "disproportionate, out of whack, unequal coverage on Russia with nothing there."

Until now, President Trump has been undeniably "soft" in dealing with Putin. He has bent over backwards to treat him as one of the most important players on the world stage, to the exclusion of many allies at the G20, he has refused to take a firm stand about what his own intelligence officials say Russia did in 2016 and is planning to do again. Although it receives less comment, the President has been relatively silent about Russia's annexation of territory and human rights abuses

The legislation that Congress is about to send to the President offers him the first real chance to show that he understands the threats that we face and the need, as our commander in chief, to protect the integrity of our election system.

The administration is trying to convince Congress and the public that there was no collusion with the Russians. This was the heart of adviser and son-in-law Jared Kushner's statement to the public and intelligence committees. "Let me be very clear: I did not collude with Russia." He said Trump's victory didn't result from meddling by the Russians: "Donald Trump had a better message and ran a smarter campaign and that is why he won. Suggesting otherwise ridicules those who voted for him."

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The rhetoric from Kushner and other members of the President's team is not that convincing to many Americans outside of Trump's base, given the contradictions, misinformation and disinformation that has come from the administration.

If the President really wants to make a strong statement about Russia, the sanctions bill is his best opportunity.

Rather than focus on a nonexistent voter fraud epidemic, the President should make clear that Russia's meddling is a key source of global instability and should not be tolerated in our elections. The President should sign this sanctions bill -- without signing additional statements that undercut the legislation -- and make clear he is sending a bold signal to Russia.