Emma Goldman's early use of 'provocateur'
The earliest instance that I can find of "a provocateur" in an article arguably written by Emma Goldman is this one from an untitled section of Mother Earth (January 1914) titled "Observations and Comments":
Good for you, Georgette [a reference to George Viereck, editor of The International magazine, who defended his decision to put a picture of a naked lady on the cover of his magazine's January issue by arguing, in part, that other publishers—specifically, "Anarchistic" ones—were "more criminal than I!"]. It is quite becoming to the self-advertised offspring of a "pure-blooded" Hohenzollern, to constitute himself a provocateur, for the safety of the crowned rulers who will no doubt know how to appreciate the delicate service. They may even subsidize a paper, in which the noble editor may glorify lickspittledom in two languages.
Note that the date of the monthly is given as January 1913 on the inside title page, but as January 1914 on the outside cover. The latter is almost certainly the correct year, as one of the items in the issue is "The Confession of a Convict" by Alexander Berkman, in the deck to which we read the following:
The 19th of December, 1913, was "confession evening" at the "Twilight Club," New York, among whose members are the "best" people, supreme court judges, and other pillars of society. "Confessions" were made by a drunkard, a dope fiend, an actress, a labor agitator, a convict, etc., some of whom spoke in complete darkness to hide their identity.)
Goldman later uses the word provocateur multiple times in "The Barnum & Bailey Staging of the 'Anarchist Plot'" in Mother Earth (April 1915):
The Pinkerton, William J. Burns, Orchard, McManigal species are of native origin. But the agent provocateur is an importation. Russia, Spain, Italy, France and Germany are full of them and their victims are legion. That is why the provocateur is hated by the workers of Europe, even more than the spy.
Heaven only knows that the spy is despicable enough, but the provocateur is the lowest of all criminals. His business is to waylay a suitable subject, and then work upon the mind of his prey through various forms of suggestion so long until his victim i a pliable as putty. Then if his victim is still unwilling to commit an act of violence, the act is committed for him. From the moment the provocateur is sent upon his mission until the final scene when his unfortunate dupe is led to his doom, the police direct, supervise and pay for the cruel job.
Other early instances of 'provocateur'
But these instances are far from the earliest instances of "a provocateur" or "the provocateur" in an English language publication.
The earliest match I've been able to find for either of these terms in English is from "Foreign Notes," in the Mineola [Texas] Monitor (May 18, 1889):
The arrest in Switzerland and expulsion from that country of Police Inspector Wohlgemutz has suddenly assumed a serious international aspect. The emperor presided at a ministerial council held at which it was decided to demand an explanation of the affair from the Swiss government. The North German Gazette declares that Herr Wohlgemutz went to Canton Aargon in the legal prosecution of his duties as police inspector of the madhouse list was arrested at the instance of a socialist who was known to be an agent of the provocateur against the German police.
This odd phrasing of "an [or the or neither] agent of the provocateur" also appears (in otherwise completely different stories) in the Sacramento [California] Daily Union (June 10, 1889), the Sacramento [California] Daily Union again (July 5, 1890), the [Cairns, Queensland] Morning Post (January 24, 1905), and the [Maclean, New South Wales] Clarence River Advocate (June 22, 1906). These appear to be an awkward effort to translate agent provocateur into English, but the result is not very satisfactory, as it invokes a shadowy figure of "the Provocateur" in whose interest the agent acts.
But finally, in 1899, the term provocateur appears independently of agent on several occasions in an article dedicated to the subject of agents provocateurs. From "Agents Provocateurs," in the [Sydney, New South Wales] Evening News (May 23, 1899):
Doubtless the spy, though not acting the true part of provocateur, excelled so as to divert suspicion from himself all the anarchists present in his denunciations of tyrants. Then, having got out alive and undiscovered, be warned his employers, and they warned all whom they thought endangered, but apparently did not warn the Empress, either because they thought she was net aimed at, or because of her erratic way of travelling they did not know where to find her.
...
Did not the late Major Le Caron declare that when working against the dynamitards in America for the British Government, he always, to avert suspicion, declared more loudly for violent means than anyone else present with the conspirators? It is pretty certain that Le Caron thus sometimes became a 'provocateur,' and, through bringing conspiracies to a head sooner than they might otherwise have come, was enabled to give Scotland Yard early and trustworthy news of intended outrages which he had taken a prominent share in promoting.
From "The Unrest in Russia," in the [Barcaldine, Queensland] Western Champion And General Advertiser For The Central-Western Districts (January 30, 1905):
The authorities have placarded Moscow with a telegram purporting to have emanated from Paris, stating that according to a London correspondent the disturbances at the Admiralty works at Libau, Sevastopol, St. Petersburg and the Westphalian collieries, were due to Anglo-Japanese agents.
A provocateur's (police) order prevents the Baltic and Black Sea squadrons proceeding to the far East, and adds that the English people have forwarded enormous sums to Russia to organise the workmens' revolt.
From "Russia's Police Fear Him: Bourtseff Has Unmasked Their Spy System," in the [New York] Sun (January, 21, 1910):
"I am a conservative revolutionist," Bourtseff said when Dr. Kaplan had explained to him the aside which he had made to the interviewers. ... ["]Though I am allied with no particular party among the revolutionists I try to work for them all by doing what I can to rid the secret associations of the provocateurs of the Russian police, who are sending men to the gallows and Siberia."
Somebody wanted to know right there what a provocateur was and what was the history of the unmasking of Eugene Azeff a little over a year ago. ...
...
Then the little doctor told what a provocateur was. ...
The phrase "a [or the] provocateur" in subsequent discussions of secret police agents in the context of Bourtseff and Azeff appear in the [New York] Sun (February 8, 1910), the New York Tribune (October 1, 1911), the [Houston, Texas] Jewish Herald (December 7, 1911) (in "A Talk on Jewish Matters," by Sholom Aleichem), the [New York] Sun (February 24, 1912), the New York Sun (June 16, 1912), and the New York Tribune (August 31, 1912).)
Moving away from Russian provocateurs, the New York Tribune offers a story of a provocateur in an Asian setting in "Books and Authors: 'American-Japanese Relations'" (January 12, 1912):
The Fleming H. Revell Company has just published, under the above title, a work discussing Japan's policies and aims in Corea and Manchuria, and chiefly her attitude toward this country. The author, Kiyoshi K. Kawakami, M.A., has been for several years a frequent and valued contributor to leading American periodicals. According to Mr. Kawakaml it is this country that is "playing the role of a provocateur."
Conclusion
All of the instances of provocateur noted in the previous section appeared in print at least 17 months before the first confirmed instance of the word in an article written by by Emma Goldman. In New York City, at least, the term provocateur for secret police agent or undercover instigator was well established by January 1914, when Goldman is first known to have used it. It therefore seems very unlikely that she deserves credit for introducing the one-word term to the English-speaking world.