As the age old saying goes, a week is a long time in politics. For almost any politician the past seven days as experienced by US President Donald Trump would have felt like an eternity, never mind seven days.

But then again we are talking about the political world of Donald Trump here, which means that things can’t be measured by any normal standards.

But even by the parameters of the Trump world, last week, as most commentators now agree, was one of the most pivotal of his presidency so far.

At its heart was a single damaging hour on Tuesday that effectively turned the President of the United States into an unindicted co-conspirator in a federal crime.

“No day during President Trump’s 19 months in office could prove as dangerous or debilitating as Tuesday,” wrote Dan Balz in the Washington Post.

“Everything that happened in a pair of courtrooms hundreds of miles apart strengthened the hand of special counsel Robert S Mueller III and weakened that of the President of the United States.”

Balz was, of course, referring to the body-blow news for Trump that his former campaign manager Paul Manafort had been convicted on multiple counts of fraud.

But Trump’s day of hell was far from over with news breaking almost simultaneously that the President’s former lawyer Michael Cohen had admitted in court to being directed by Trump to break federal campaign finance law by offering “hush money” to cover up affairs with a former porn star and a model.

Both Manafort and Cohen were convicted on eight counts and while not directly related to allegations of collusion with Russia, it provides the surest signs yet that special counsel Mueller’s far-flung investigation into Trump’s inner circle is closing in on the President himself.

But a week that began with bad news closed with worse news for Trump. Offers of full immunity for a number of Trump insiders to spill all to federal prosecutors is piling the pressure on the President and sure to be giving even “Teflon Don” a few sleepless nights.

As with all the President’s men who have fallen of late, Paul Manafort, Michael Cohen and Trump’s former national security adviser Michael Flynn, offers made to them of plea bargaining appear to be focusing minds.

Increasingly, it appears those implicated may not be willing to jeopardise their own freedom or receive maximum sentences in order to defend Trump.

In the case of those other individuals now being offered full immunity they need only tell the truth and all they know to be guaranteed protection from prosecution or any legal reprisals.

In other words, even if they facilitated, participated in, or otherwise aided any crimes, they would not be charged in return for spilling the beans.

Such an inducement is perhaps about as good as it’s going to get for many who see themselves being slowly but inevitably sucked into any wrongdoing that Trump may or may not have have carried out.

Perhaps key among those offered the full immunity deal is Trump’s top moneyman, Allen Weisselberg. No-one knows, of course, what Weisselberg may say, but what is known is that there is little, if anything, he doesn’t know about Trump’s finances, business deals and taxes.

Writing about the significance of Weisselberg as the man in the know, New Yorker columnist Adam Davidson on Friday described the CFO as the man to whom most Trump watchers most want to speak. He is also, as Davidson added, the man who has, for decades, been the most circumspect.

“There are many open questions about how, precisely, the Trump Organisation has made and spent its money in recent years. There is, for example, a question about where Trump got more than two hundred million dollars in cash to buy and lavishly upgrade a money-losing golf course in Scotland,” says Davidson.

Deals done with those suspected of money-laundering for Iran’s Revolutionary Guard, an FBI investigation into funding sources for property in Vancouver and a hotel in Toronto are just some of the question marks hanging over Trump’s business empire.

“These are just a handful of the many business deals that Trump has conducted that have signs of possible money-laundering, tax evasion, sanctions violations, and other financial crimes. Many of the key questions about Donald Trump revolve around his funding sources and his business partners … Trump, himself, may not know the exact answers to all of these questions. Perhaps Allen Weisselberg does,” Davidson concluded.

For years many have tried, unsuccessfully to gain an insight into Trump’s closed financial dealing and tax affairs. Public advocacy groups have sought his tax returns and failed. Even his ex-wives, and by one account his bankers, haven’t been able to get a full view of Trump’s finances.

The latest revelations by people like Manafort and Cohen open up new opportunities for investigators.

“Because there are tax implications to all these transactions, it even opens up Trump’s tax returns to state and federal prosecutors: The Holy Grail,” Frank Agostino, an attorney in New Jersey, who formerly prosecuted US tax cases, told Bloomberg Business News last week.

Though mundane sounding and lacking much of the high drama that usually surrounds Trump’s affairs, tax law nonetheless has been a fundamental tool for authorities since the days of mobster Al Capone.

Those close to Trump’s finances like Weisselberg, should they opt for immunity deals, will only make such tax probes easier.

Enter also David Pecker, the publisher of the National Enquirer. Pecker’s publication buried the stories relating to Trump’s dalliances with model Karen McDougal and porn star Stormy Daniels, and the resulting payoffs.

Pecker now may also be willing to share anything he knows about these payments with federal authorities without fear or threat or prosecution. With such unprecedented pressure mounting on the President it’s not surprising that many commentators are now re-examining Trump’s capacity to weather such a political storm.

Investigations are one thing. The other I-word – “impeachment” – is something else entirely.

Last Tuesday’s convictions of Manafort and Cohen help build an increasingly compelling case for impeachment, given it’s now clear the President engaged in at least one conspiracy to hide the truth from the public in an election he won with a tiny margin in three states.

As Cohen’s lawyer Lanny Davis said after Tuesday’s court ruling, “if those payments (of hush money) were a crime for Michael Cohen, then why wouldn’t they be a crime for Donald Trump?”.

Starting any impeachment process against the President would not be easy, of course. Currently it would require a mass revolt by Republicans against Trump in the House of Representatives now controlled by the GOP, something even less likely than normal to happen with midterm elections on the horizon.

Those elections are now little more that 11 weeks away but could still effectively serve as a referendum on whether or not to press ahead with impeachment proceedings.

It would certainly be much more likely if the Democrats were to gain ground in the House, where the Republicans currently hold 51 seats to their 46.

Some US political commentators firmly believe though that whether Trump recognises it or not, his main and perhaps only hope for clinging to office is that Republicans hold the House in November.

In the meantime, the President has more than than enough to contend with, not just domestically but overseas.

If the past week was damaging for Trump at home then yet more evidence surfaced of his equally dysfunctional foreign policy.

Richard Haass, US diplomat and president of the Council on Foreign Relations, summed up the frustration and concerns over Trump’s failure to address pressing international issues in a wry tweet a few days ago.

“I understand the focus on politics here at home, but 1) NK is not denuclearising; 2) Venezuela is on the precipice; 3) a crisis with/over Iran is brewing; 4) climate change is worse sooner than predicted; 5) US relations w China and Russia are at post-Cold War nadir. just sayin”.

It was barely a few months ago that Trump bragged that “everybody thinks” he should win a Nobel Peace Prize over his “dazzling diplomatic achievement” following the summit meeting with North Korean leader Kim Jong-un.

The meeting, Trump insisted, was a great success and North Korea was “no longer a nuclear threat”. But only this weekend, in a dramatic shift in tone, the President abruptly cancelled US Secretary of State Mike Pompeo’s planned trip to North Korea, conceding for the first time that his effort to get Pyongyang to denuclearise has stalled since his Singapore chat with Kim.

Trump partly blamed China for the lack of progress and suggested that talks could be on hold until after Washington resolved its bitter trade dispute with Beijing.

“Because of our much tougher trading stance with China, I do not believe they are helping with the process of denuclearisation as they once were (despite the UN Sanctions which are in place),” Trump said in one of his ubiquitous tweets.

This latest North Korea foreign policy setback was also compounded this past week after Trump created a diplomatic spat out of nothing by bulldozing his way into one of South Africa’s most racially-charged political debates, again via Twitter.

In his tweet. Trump asked Mike Pompeo “to closely study the South Africa land and farm seizures and expropriations and the large scale killing of farmers”.

Trump’s tweet was unusual, not least given that since becoming President he has shown little foreign policy concern for much of the continent and those African nations he has slagged off as “s***hole countries”. What,then, could have motivated him to make such remarks?

Despite enquires from numerous media sources, the White House remained vague as to where Trump got his information about “large scale killing of farmers” in South Africa.

It would appear, however, that Trump’s motivation for the tweet was based on a spurious Fox News Tucker Carlson report pushing a white conspiracy theory that white farmers in South Africa are being persecuted and murdered in Zimbabwe-style land grabs.

Many such theories are peddled by the likes of white-supremacist websites such as Stormfront, which has a section devoted to South Africa.

Much of Stormfront’s material appears to have originated with a political group called AfriForum that many people in South Africa attest is nothing more than a hard-core racist group serving extremist Afrikaner interests.

Human rights and monitoring groups like Africa Check, the non-profit organisation set up to promote accuracy in public debate and the media in Africa, confirmed they could find no data to substantiate the US President’s claims.

Not surprising, then, that Trump’s remarks drew a sharp rebuke from the South African government, who said that it “totally rejects this narrow perception which only seeks to divide our nation and reminds us of our colonial past”.

Since the diplomatic fallout with South Africa, speculation has grown that Trump’s strategy might well have been to use such a charged racial issue in order to galvanise his core support base in the US, while drawing attention away from the real challenges his presidency now faces as a result of last Tuesday’s court rulings and ongoing investigations.

If that proves to be the case then it points to a president increasingly desperate.

Many times before, of course, the Trump presidency has been pronounced doomed. But as Robert Mueller’s investigation continues to burrow deeper into Trump world, perhaps for the first time we are beginning to see real chinks in the President’s armour.

Trump, in characteristic style, dismissed much of what confronted him last week. There is no escaping the fact though that it solidly cemented corruption as the theme underpinning his tenure in the White House.

More than ever that looks to be what will ultimately unravel his presidency.