Watching the latest example of Gerry Adams trying to defend the indefensible, it's hard to avoid the comparisons with the movie classic 'Godfather' and the Michael Corleone character.
In the first of the trilogy, Michael assures his wife that in five years' time the Corleone family will be completely legitimate. But, despite his desperate desire to achieve that, it proves far more difficult than envisaged. By 'Godfather III', an exasperated Michael sighs: "Just when I thought I was out, they pull me back in."
Privately, that must be what Adams and other senior Sinn Féin people must be feeling. The war is over, thanks in no small part to Adams's efforts, but its terrible legacy continues to 'pull back' the party.
The twin strategy of the armalite in one hand and the ballot box in the other is gone. But the hard men who carried the armalites are not. And, despite the strong growth of Sinn Féin in the past 20 years, there are regular reminders of that - reminders incompatible with a democratic political party.
The latest example, Adams's defence of Thomas 'Slab' Murphy following his tax evasion conviction, must have Sinn Féin TDs tearing their hair out. They know how this looks. A year ago, Mary Lou McDonald stood up in the Dáil and named former politicians accused of having off-shore bank accounts on the flimsiest evidence imaginable. And now, her leader is describing a convicted tax evader as a "good republican".
How can the party's taxation policy, based on taxing the wealthiest the most, have any kind of credibility now? A raid on Murphy's farm in 2006 by officers on both sides of the border found €630,000 in cash and cheques. Yet Sinn Féin is willing to defend him. This is a party that prides itself on representing the disenfranchised against the establishment - as long as it's not republican establishment.
Adams's comments about the Special Criminal Court have only added to the party's problems. Leaving aside the irony of anybody with links to the IRA questioning the need for such a court, it will be seized on by the party's critics as evidence the republican movement's traditional ambivalence towards the institutions of the State still exists.
And perhaps most damaging for the party, it leaves Adams and Sinn Féin open to the charge that it cares more about what Slab Murphy thinks than about the average voter. It was telling that during the height of the scandal caused by Mairia Cahill's revelations, Adams returned to the party's heartland of West Belfast to make his speech defending the party and denouncing his critics. The suspicion at the time was this was a deliberate choice aimed at sending a clear signal - as much to the bright young things in the party south of the Border as anybody - about from where Sinn Féin drew its power.
So who's calling the shots in Sinn Féin? And why does Adams feel the need to back a convicted tax evader, something none of the leaders of the other political parties would do so overtly? Why does Adams, who will probably poll a quota-and-a-half in Louth in the general election, still need the hard men on his side? Why can't he just cast them off as de Valera did 80 years ago?
The answers to these questions are complex. There are indications of serious internal tensions in the republican movement. Reports say Murphy and his associates are deeply unhappy and feel "betrayed" by events, believing they were to be left alone as part of the Peace Process.
That's the reality Adams has to, or has chosen to, deal with. He has successfully managed a balancing act between the old guard and what the party needed to move towards conventional politics. But the difference is Sinn Féin is now a serious player in the South.
The party should win 25-plus seats in the election. It could potentially be involved in government. And that seriously raises the bar.
There is a percentage of the electorate, largely disenchanted with the Government and the State, for whom the latest controversy won't matter. Sinn Féin is going to have a good election even if this controversy runs to the eve of polling - which it conceivably could do given Murphy is due to be sentenced early in the new year.
However, there will be other voters for whom this - allied to the Cahill revelations, the statements from the PSNI about the IRA and the ongoing questions about funding sources - raises further questions about the party's fitness for government.
Is Pearse Doherty fit for government? Absolutely. He has shown his abilities in the banking inquiry and elsewhere. The same holds for Mary Lou McDonald, Pádraig Mac Lochlainn, Peadar Tóibín and many others.
But, unlike the other parties, Sinn Féin is about far more than its parliamentary party, even if that's not entirely visible to voters.
It's pointless anyone in the media saying it's time for Adams to make way for a new generation, untarnished by the Troubles - that's just not how Sinn Féin works.
Adams will go at a time of his choosing. The view being in republican circles that he's earned that right.
Fair enough. But until that happens, and it's the new breed driving the party, these legacy issues will keep pulling Sinn Féin back into the past, instead of pushing on for government.
Shane Coleman presents the Sunday Show on newstalk.com at 10am