The phrase a nail in the coffin and variants denote something that hastens, or contributes to, the end of the person or thing referred to.
The image is first recorded in the following passage from Ode XV of Expostulatory Odes to a Great Duke, and a Little Lord. By Peter Pindar, Esquire. A New Edition (London: G. Kearsley, 1789), by the English satirist John Wolcot (1738-1819):
Care to our coffin adds a nail, no doubt;
And ev’ry grin, so merry, draws one out.
The earliest occurrence of the phrase that I have found is from the eighth open letter that the English political writer Thomas Paine (1737-1809) addressed to the citizens of the United States, published in the Aurora General Advertiser (Philadelphia, Pennsylvania, USA) of Friday 7th June 1805—Paine was denouncing the Federalist party, which advocated a strong central government and the maintenance of good commercial and diplomatic relations with Britain:
Every thing this faction does hastens its exit. The abusive vulgarity of Hulbert1, a pettiyfogging [sic] attorney of Sheffield, in Massachusetts, and one of its legislators, has contributed to bring forward the funeral. In his late unprincipled speech in the legislature of that state, he has driven another nail in the coffin of the federal faction […].
1 John Whitefield Hulbert (1770-1831) was a U.S. lawyer and politician.
Every battle which is fought and won by the French is an additional nail in the coffin of the liberties of the world.
The following is from The Taunton Courier, and Western Advertiser, for Somerset, Wilts, Dorset, Devon, and Cornwall (Taunton, Somerset, England) of Thursday 3rd September 1812:
The outrageous violence on the claim of common justice, manifested by Mr. Cobbett2, in the conduct of his Political Register, was very glaringly exposed by Mr. Elton3 […].
[…] No wonder that Mr. Cobbett is angry with Mr. Elton, who, by exposing the obliquity of his personal feelings and the dereliction of his public duty, has clenched the nail in the coffin of the Political Register.
2 William Cobbett (1763-1835) was an English author and political reformer; he founded the periodical Cobbett’s Political Register in 1802.
3 Charles Abraham Elton (1778-1853) was an English officer in the British Army and an author.
The following is from The Maryland Gazette and Political Intelligencer (Annapolis, Maryland, USA) of Thursday 29th August 1816—in March 1816, Congress had passed the Compensation Act, which changed the mode of compensating the members of the Senate and of the House of Representatives; it had abandoned the $6 per diem in favour of an annual salary of $1500:
From the People’s Friend.
The compensation bill is a measure so base in itself, so shameless in all its circumstances, so dangerous to our constitution, and exhibits democracy in so clear and true a light, that too much can not be said about it—the people cannot too often recur to it. We publish the following history of this democratic monster, because we know it to be true in fact. It places the subject in a true point of view, and we hope will clinch the last nail in the coffin of Maryland democracy—We earnestly invite every man, federalist or democrat to its perusal.
A person signing themself ‘J. H. R.’ used a variant of the phrase in Boswell’s Visit, an article about poets published in the Chester Courant, and Anglo-Welsh Gazette: Advertiser for Cheshire, Salop, Lancaster, Stafford, and Derby (Chester, Cheshire, England) of Tuesday 31st December 1816:
Rogers4 writes good polished notes, but his verses are gloomy and hollow: he puts brass headed nails on a coffin. He clouds the future with the shadows of the past.
4 Samuel Rogers (1763-1855) was an English poet.
Ironically, Isaac Coffin (1759-1839), Member of Parliament for Ilchester (in Somerset), and retired officer of the Royal Navy, used the phrase during a debate on the Salt Tax at the House of Commons on Monday 1st April 1822—as reported the following day by The Public Ledger, and Daily Advertiser (London, England):
Sir I. Coffin was anxious to drive a spike nail into the coffin of this oppressive tax. He trusted Gentlemen would remain firm at their post, and fire broadside after broadside at his Majesty’s Ministers until they were obliged to give up this obnoxious impost.
In the early 19th century, the phrase was particularly used in reference to “dram-drinkers”, i.e. to habitual drinkers of spirits—the earliest occurrence of this usage that I have found is from the Lansingburgh Gazette (Lansingburgh, New York, USA) of Tuesday 24th January 1809:
A good Comparison.—It is usually said of dram-drinkers, that every dram they take, is “another nail driven into their coffins.” This has been almost always the case; and the unfortunate dram-drinker finds, when hope is hopeless, that he has irretrievably clenched the last nail. In like manner, every day that the embargo is continued, is another nail driven into the democratic coffin. Like the dram-drinkers, the infatuated embargoites seem determined to clench the last nail.
In British English too, the phrase was used in reference to habitual drinkers of spirits; to add another nail to the coffin occurs, together with to keep the nails out of one’s coffin, in Life in London; or, The Day and Night Scenes of Jerry Hawthorn, Esq. and his elegant Friend Corinthian Tom, accompanied by Bob Logic, the Oxonian, in their Rambles and Sprees through the Metropolis (London: Sherwood, Neely, and Jones, 1821), by the British journalist and author Pierce Egan (1772-1849):
Most persons who are in the habit of going from one public-house to another, and drinking a number of drams in the course of a day, in order to allay the heat or thirst arising from the pernicious use of such quantities of ardent spirits, frequently take a glass of porter, which is termed a cooler, a damper, &c.; and too many individuals, hard drinkers, flatter themselves that, from such sort of care, they are keeping the nails out of their coffins,* till the trembling hand, the diseased appetite, and the debilitated constitution, lamentably point out the fatal error, too late to be corrected.
* A glass of spirits is termed, among the wet ones, adding “another nail to the coffin.”
The following is an illustration for Cripple Buries Body of His Old Friend. Builds Coffin With His Own Hand and Conducts the Funeral Himself, published in The St. Louis Republic (St. Louis, Missouri) of Thursday 22nd November 1900—James Thornton, an old, one-legged soldier, is building the coffin of his friend, Oliver Turner:
When at last the boards had been fashioned and fitted into the crude semblance of a coffin, Thornton […] exhibited several lengths of cloth. It was cheap, but it was black. With brass-headed tacks he nailed it on, and on the lid made a faint effort at a studded design.
It was ten minutes to 4 o’clock in the afternoon when the coffin was finished and the old gray mule was driven around into the alley. Thornton let down the end-gate of the wagon, the black-covered box, studded with the brass-headed tacks, was lifted in, and the journey to the morgue was made.