How much longer will Mary Lou have to wait in wings?
As the latest skeleton to tumble from Sinn Fein's closet makes headlines, it seems the party's deputy leader would turn a blind eye to just about anything to succeed Adams as president
Mary Lou McDonald is presumably not a big fan of Fawlty Towers. She once tried to quote from it in a Dail speech by comparing her opponents to the sitcom's hapless Spanish waiter, Manuel. Unfortunately for Sinn Fein's deputy leader, her quip backfired when she referred to the character played so memorably by Andrew Sachs as "Manolo".
Now, in the week following Sachs's death, McDonald finds herself accused of borrowing Manuel's catchphrase, "I know nothing". With Sinn Fein reeling from allegations that some of its best-known politicians may have information about an IRA murder, the party's leader-in-waiting has firmly adopted a see no evil, hear no evil approach.
Once again, the question is being asked in Leinster House, is there any Sinn Fein scandal that McDonald is not prepared to turn a blind eye to in order to achieve her long-term ambition of succeeding Adams?
In case there was any doubt about that ambition, McDonald also used a newspaper interview this week to make it crystal clear.
"When there is a vacancy - and there is no vacancy now - I will be asking for my name to go forward and then it is a matter for membership," she said.
If Adams decides to reward her loyalty with his backing, she would be all but unstoppable - as long as they have not both destroyed each other's credibility by the time that day arrives.
The latest skeleton to tumble out of Sinn Fein's closet dates back to March 1983, when Mary Lou was 13 years old. Brian Stack, a prison officer at Portlaoise, where many republican convicts were held, was shot in the back of the neck after leaving a boxing match at Dublin's National Stadium.
He was left paralysed and suffered for another 18 months before dying at the age of 47.
For several years now, Mr Stack's sons, Austin and Oliver, have been lobbying Adams to help them discover the murderers' identities. In 2013 they travelled with him in a blacked-out van to an unknown location along the border, where a former Provo chief admitted that IRA members had been responsible.
He also claimed that the killing had not been sanctioned by the IRA leadership and that the renegade gunman had been "disciplined".
Last week, the story took a new twist. The Irish Independent revealed that Adams sent an email to Garda Commissioner Noirin O'Sullivan three days before February's General Election, supplying the names of four people who may have information about the killing of Mr Stack.
This is where Mary Lou McDonald comes in. If any other political party was rocked by such serious allegations, the deputy leader would be putting pressure on his or her boss to clear them up.
Instead, McDonald has declared that although she knows who the Sinn Fein people alleged to have information about Mr Stack's murder are, she has no intention of personally getting involved.
"I think that people have an entitlement to their good name," she said last weekend. "There would be no useful purpose with me having a conversation with anybody on this issue."
McDonald also made the extraordinary claim that Adams had given the Garda all relevant information without delay. By his own admission, this is wildly inaccurate, and he did not contact O'Sullivan for another two-and-a-half years.
Adams's Dail statement on Wednesday night, which McDonald did not attend, descended into chaos when the Fine Gael TD Alan Farrell used parliamentary privilege to name Dessie Ellis and Martin Ferris.
Unfortunately for Mary Lou, her own past behaviour makes it difficult for them to take the moral high ground here. In 2014, she named six former politicians who allegedly held illegal offshore Ansbacher accounts - and was later found to have abused Dail privilege herself. The named individuals were subsequently found to be innocent.
Of course, this week is by no means the first time that Mary Lou has tried to bail Gerry out of a sticky situation. When he was arrested in 2014 over the murder of mother-of-10 Jean McConville, she insisted that his detention was "politically motivated" by "old guard elements" within the PSNI and unionism. When Mairia Cahill accused him of covering up her rape at the age of 16 by an IRA man, McDonald responded that some of Ms Cahill's claims about Sinn Fein were "simply not true".
When Adams defended the alleged IRA godfather and convicted tax cheat Thomas 'Slab' Murphy as "a good republican", McDonald backed him up by saying Murphy was "very nice... a very typical rural man".
Most embarrassingly of all, McDonald has felt obliged to say on countless occasions that she believes Adams when he says that he was never even a member of the IRA.
The defining image of Mary Lou McDonald comes from a TV3 documentary about Sinn Fein made by Ursula Halligan in 2013. It shows the Dublin Central TD shopping in her local Superquinn, checking the price of prawns and then moving to the breakfast cereal aisle. Asked about her commitment to a united Ireland, she replies: "I'm just looking for Cheerios ... Cheerios and a united Ireland."
No spin doctor could have come up with a better illustration of how McDonald has the potential to transform Sinn Fein's electoral fortunes.
As a middle-class working mother who has clearly never planted a bomb or gone to jail, she could certainly expand the party's base far beyond its republican heartlands.
Hillary Clinton failed to crack the glass ceiling in last month's US election, but a female leader might just help Sinn Fein to crack its own glass ceiling of support, which seems solidly stuck somewhere around 15% in the Republic.
By common consent, McDonald is her party's best performer, both in the Dail and across the airwaves. She often exudes an icy contempt for opponents. She is always impeccably well-briefed, while Adams's confused comments about tax policy in a disastrous radio interview during the last election led to him being dubbed "a man who takes off his socks to count to 20".
McDonald's critics sometimes wonder how a Rathgar woman educated at Notre Dame convent school and Trinity College could possibly have ended up in Sinn Fein. Dig a little deeper into Mary Lou's background, however, and you discover that she comes from a family steeped in Irish nationalism.
Her mother's uncle was one of the Grey Abbey Martyrs, seven anti-Treaty IRA activists who were arrested by Free State Forces and executed in 1922.
Despite attempts to bolster her republican credentials, McDonald is sometimes labelled a 'me feiner', rather than a Sinn Feiner.
She was briefly a member of Fianna Fail in the late 1990s and, according to some accounts, only left because her Dail ambitions were frustrated by the local TD Brian Lenihan Jnr.
She strongly disputes this, insisting that she switched parties after realising Fianna Fail was far too conservative for her.
Even assuming that Adams survives his latest brush with scandal, he is now 68 and seems unlikely to fight another election. McDonald's only credible leadership rival in the Dail is finance spokesman Pearse Doherty, who has said that having young children rules him out for now.
At the public accounts committee earlier this month, McDonald was in scathing form. "Do you know the expression 'eejit'?" she asked the MD of a bank that had advised the National Asset Management Agency. "It's an Irish term. A patsy. They made an eejit of you."
The problem for McDonald is Adams has been making an eejit of her on a regular basis - and she seems either unwilling (or unable) to do anything about it.