Image caption President Richard Nixon resigned over the Watergate scandal in 1974

Former CBS news anchor Dan Rather has compared the controversy over links between members of President Donald Trump's team and Russia to the Watergate scandal.

Rather, who was for decades one of the best known and most trusted figures in US journalism, said in a Facebook post: "Watergate is the biggest political scandal of my lifetime, until maybe now."

He said Watergate, which brought down the presidency of Richard Nixon in 1974, had been a nine-out-of-10 on a scale of crisis for the US government, while "this Russia scandal is currently somewhere around a five or six".

He continued: "But it is cascading in intensity seemingly by the hour. And we may look back and see, in the end, that it is at least as big as Watergate. It may become the measure by which all future scandals are judged.

"It has all the necessary ingredients, and that is chilling."

The post has been shared more than 88,000 times and has generated nearly 200,000 reactions.

Image copyright Facebook Image caption Initial reaction to Rather's Facebook post blamed Republicans

Later in the post, Rather, who is often viewed as taking a liberal perspective, strongly criticised the White House, accusing it of a "spigot of lies" and saying it had "no credibility on this issue".

"I would also extend that to the Republican Congress, who has excused away the Trump Administration's assertions for far too long," he said.

Rather also promoted his post on Twitter, generating more than 13,000 retweets and 22,000 likes.

President Trump's latest response over the Russia controversy was retweeted more than 14,000 times and liked by nearly 60,000 accounts.

Both posts have also generated many critical comments.

Image copyright Twitter

Likes and scrutiny

A number of comments by Rather's Facebook followers, several of which had likes in the tens of thousands, suggested that the way Republican politicians scrutinised President Nixon was the benchmark that should be applied now.

Since his post was published, leading Republicans such as Devin Nunes, John Cornyn and John McCain have urged further investigation.

Some commenters on social media aimed particular criticism at Jason Chaffetz, the Republican chair of the House Oversight Committee, who has said his panel will not look into Gen Flynn's stepping down as Mr Trump's national security adviser.

Image copyright AP Image caption Dan Rather was a news anchor on CBS until the mid-2000s

Cliches and analogies

Likening US political scandals and embarrassments to Watergate may have lost some of its force over the years, becoming almost a cliche.

Mr Trump has himself used the comparison, at an election rally last year, saying the row over Hillary Clinton's emails was a scandal "bigger than Watergate".

Some social media users have suggested an alternative analogy for the present situation, saying a better comparison may be to the Iran-Contra affair, in which journalists exposed the illegal funding of anti-Sandinista forces in Central America in the 1980s.