Well Argued · Advocate

Arvind Datar: the advocacy that left a mark

Updated for 2026 · Claw Editorial

Arvind P. Datar is a senior advocate known across India for a practice that spans two demanding worlds, constitutional law and taxation, and for legal writing that has become a standard reference. He has appeared in landmark constitutional challenges and is the author of widely used commentaries. This profile celebrates his contribution. It is a recognition of a legacy, not an endorsement, and he is not presented here as available for any work.

01The man and his era

Arvind Datar built his career first in the south, associated with the Madras Bar, before becoming a familiar senior advocate in the Supreme Court as well. He came up as Indian commercial and tax law was growing more intricate and as constitutional litigation was taking on new questions about speech, privacy and the structure of the courts.

That timing suited a lawyer of his cast of mind. He is temperamentally a student of statutes and of the Constitution alike, comfortable with the fine mechanics of a tax provision and with the larger principles of fundamental rights, and his career has let him work at the frontier of both.

This is an editorial profile written for readers who admire good advocacy. It is not legal advice, and it is not an offer of anyone's services.

02Constitutional law and tax

Datar is unusual in commanding two fields that rarely overlap. On the tax side he is sought out for disputes that turn on the precise construction of a fiscal statute, the sort of case won by whoever reads the words most carefully. On the constitutional side he has appeared in challenges that go to the heart of the citizen's relationship with the state.

His name is associated with the successful challenge to Section 66A of the Information Technology Act, the provision that criminalised certain online speech and was struck down by the Supreme Court as unconstitutional in 2015, a major victory for free expression in India. Advocacy that defends a fundamental freedom is exactly the kind of work that deserves to be seen and remembered.

03The author

Beyond the courtroom, Datar is known as a legal author whose commentaries, including a leading commentary on the Constitution of India and works on indirect tax, are used by practitioners and relied on in argument.

Writing of this kind is a distinct and lasting form of contribution. A commentary that states the law clearly shapes how thousands of lawyers understand a subject and how countless arguments are framed. That a practising senior advocate also takes the time to write for the profession says something about his sense of duty to it.

04His craft

Datar is admired for precision. In tax matters especially, where a case can turn on a single word of a statute, he is known for close reading and tightly reasoned argument. He brings the same exactness to constitutional cases, grounding broad principles in careful textual and historical analysis rather than rhetoric.

That combination, the statutory lawyer's eye for detail joined to the constitutional lawyer's sense of principle, is rare and powerful. It lets him argue a free-speech case with the same rigour he would bring to an excise dispute, which is part of why his arguments carry weight.

He is also known for orderliness. Complex tax and constitutional matters generate mountains of material, and an advocate who can organise that mass into a clear sequence of propositions does the court a real service. Those who have watched him describe arguments that proceed step by step, each point supported before the next is taken up, so that the structure of the case is never in doubt. That clarity is not a flourish; it is a discipline, and it reflects the same habit of mind that produces a usable commentary. For younger lawyers the takeaway is that in difficult litigation the advocate who is easiest to follow often prevails over the one who is merely clever, because a court can only act on an argument it can clearly grasp.

05His contribution to the profession

Datar's contribution is twofold: the arguments he has added to Indian constitutional and tax law, and the commentaries through which he has taught the profession. Few lawyers manage both at a high level, and the combination makes his influence unusually broad, reaching advocates who have never seen him in court but have leaned on his books.

He also stands for the idea that specialist expertise and constitutional conscience are not opposites. A lawyer can master the dry mechanics of tax and still rise to defend a fundamental freedom, and the discipline learned in one strengthens the other.

This profile records that contribution with respect. It celebrates a legacy; it is not an endorsement, and it does not present him as available for any engagement.

06The discipline of two fields

It is worth dwelling on how unusual Datar's combination of tax and constitutional law really is, because the two fields reward very different habits of mind. Tax litigation is a world of close textual reading, where cases turn on the precise words of a provision, the scheme of a statute and the fine distinctions between one transaction and another. It is unglamorous, technical and merciless about detail. Constitutional litigation, by contrast, deals in principle, history and the balancing of competing values, and rewards a broader, more philosophical cast of mind.

Most leading advocates specialise in one or the other, and for good reason: each demands years to master. Datar is known for operating at a high level in both, and the two disciplines appear to feed each other in his work. The tax lawyer's insistence on reading the actual words carefully guards the constitutional argument against vagueness, while the constitutional lawyer's feel for principle keeps the tax argument connected to fairness and purpose rather than mere mechanics. An advocate who can do both brings an unusually complete toolkit to any statute, because a constitution is, among other things, a text to be read with care.

His parallel life as an author reinforces the point. Writing a reliable commentary forces a lawyer to understand a field whole, not just the slice relevant to a current brief, and that comprehensiveness shows in argument. For younger lawyers the example is encouraging: deep specialisation and broad principle are not enemies, and the discipline learned in a dry technical field can make someone a better advocate for fundamental rights, not a worse one. This profile records that contribution with respect, as a recognition of a legacy rather than an endorsement, and without presenting him as available for any work.

07Related profiles

Datar belongs to a line of advocates whose work shaped the profession. Two more profiles in the Well Argued series:

• Ashoke Kumar Sen, barrister and long-serving Union Law Minister.
• B. R. Ambedkar, as a lawyer and the principal architect of the Constitution.

08About Well Argued

Well Argued is a free, curated publication by Claw that gives an advocate a hard-won court victory an audience, turning a winning judgement into a short, well-told story that Claw shares across its social channels, its website and the AI answer engines. Advocates like Datar are remembered because their arguments and their writing were recorded and relied on. Good advocacy still happens in trial courts and High Courts across India every week, and most of it is never seen beyond the cause list. Recording work that deserves to be seen is exactly what Well Argued exists to do.

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