Some Observations Regarding Pursuit of Mandamus Without a Lawyer:
Technically, yes of course an individual can apply for Mandamus pro se.
If you need to look up "pro se" to be sure what this means, however, you almost certainly need a lawyer. Even if you do know a fair amount of legalese-Latin, though, I emphatically concur in the cautions expressed by jhjeppe.
An application for a Writ of Mandamus is, by definition, an extraordinary remedy. It is not a routine application for judicial review. A lawyer here I know told me, back when he was clerking for the Court, that a huge percentage of applications for review submitted to the Federal Court, by lawyers, fail for technical reasons, no chance for the merits of the case to ever be heard because the procedural requirements are complicated enough that even lawyers have difficulty getting it right. And that is about applications for ordinary review. But, again, the application for a Writ of Mandamus is an extraordinary process.
Oh sure, almost anyone can complete a form, pay a filing fee, file the form and do the other procedural steps to commence the legal process. And soon find their case dismissed for a technicality. And all that money saved by not hiring a lawyer, hopefully you still have it, because the Federal Court may require you to pay the Minister's costs. Problem is, a lawyer for you probably could have come a lot cheaper than what the Minister's legal costs are, meaning it could end up costing you a lot, a lot more than what hiring a lawyer would have cost.
I do not disagree with the proposition that qualified citizenship applicants should not need to pay for a lawyer to get their application processed in a reasonable time (let alone take the risk of having to pay the Minister's legal costs). Indeed, CIC should process all applications, even those made by the unqualified, within a reasonable time. That it should be so, though, does not make it so. And this is particularly true in regards to pursuing a Mandamus application without competent legal counsel.
All that said, sure, of course some individuals may very well be savvy about legal process, capable of doing the homework, including a lot of legal research, competent in recognizing the necessary steps that must be taken before an application for Mandamus can be legitimately made (at minimum, a proper request for the Minister to do a legally mandated act must be made and denied), identifying what the relevant issues and factors are in establishing grounds for the particular relief being requested, and being able to properly identify and request what recourse or remedy is available and appropriate (including properly framing the prayer or request for that remedy). And this is one area of legal process in which technicalities loom large. Miss a requisite, for example, the court does not return the application as incomplete and give you an opportunity to resubmit it; the Minister will, instead, make the motion to have the application dismissed and probably ask for costs, and the Federal Court will dismiss it, with a significant risk the court will indeed order the party bringing the flawed application to pay the Minister's costs.
Sure, if one application gets dismissed, you can file another. If it is not perfect, including establishing the grounds for the relief requested, the risk of having to pay the Minister's costs in the second application increase dramatically.
And, to be clear, mere delay, regardless of the length of the delay, does not constitute grounds for Mandamus. If that's the basis of the application, you lose, you lose at the risk of being ordered to pay the Minister's costs. (And if you do not understand why I say this, pursuing a Writ of Mandamus pro se is definitely out of your league.)
It warrants noting that there are many reports indicating reluctance among more than a few lawyers to take a citizenship mandamus case. Lawyers do not casually turn away clients or their money. There is usually a reason there is reluctance to take on a Mandamus case relative to this or that applicant. And the absence of a good case is probably the most common reason.
I do not mean to discourage pursuing recourse for excessive delays. In particular, there are some individuals for whom a Mandamus application is very much appropriate, perhaps overdue. But make no mistake, it's a big league venue. It is not like applying for a job and not getting it. It is not like making a small claims case and the judge tries to figure out what's the best outcome based on basic principles justice and fair play, with a less than technical application of law.
I do mean, however, to discourage the encouraging of others to pursue applications for Mandamus pro se. It is bad advice, at best. And ultimately, most applications are now on track to move to the next step, if not totally resolved, in the somewhat near future, which would of course eliminate the basis for a Mandamus application, rendering it moot. Anyone may, such as Decius seems inclined, attempt to pursue a Writ of Mandamus without a lawyer. But any suggestion, let alone explicit advice to others, that they too should pursue Mandamus without a lawyer, should be summarily dismissed (at the least as reckless).
In other words: If it seems like time to take legal action to compel CIC to act on a case, see a lawyer first -- last I knew, consultations, real consultations, tend to cost $300 to $500. The more homework and research the applicant does before going to the lawyer, and the better organized the applicant is when taking documentation to the lawyer, the more bang for the buck the applicant can get in a consultation. Skip the free consultations, especially for something this complicated, something this factually driven relative to the particular individual's case.