It does not appear the treaty ever resulted in direct action by the Romans in support of the Hasmoneans, but it may have deterred the Seleucid Empire, the regional power in the era, from taking more extreme measures against Judea.
[1] During the early 2nd century BCE, Rome's power and influence in the Eastern Mediterranean region was growing, while that of the Hellenistic Greek successor states formed from the conquests of Alexander the Great was declining.
[2] The treaty was negotiated during the Maccabean Revolt, an attempt by Judeans first to stop Seleucid decrees against the practices of Second Temple Judaism, and later to acquire autonomy for the region.
Their mission may have been aided by the Roman Senate being unhappy at Demetrius escaping from Rome and taking the Seleucid throne, against their wishes of keeping the pliant and weak young Antiochus V in charge.
[4] And this is a copy of the letter that they wrote in reply, on bronze tablets, and sent to Jerusalem to remain with them there as a memorial of peace and alliance: May all go well with the Romans and with the nation of the Jews at sea and on land for ever, and may sword and enemy be far from them.
To the enemy that makes war they shall not give or supply grain, arms, money, or ships, just as Rome has decided; and they shall keep their obligations without receiving any return.
But their current rulers [Hyrcanus and Aristobulus], who had abolished their ancestral laws, had unjustly forced the citizens into subjection; with the help of a large number of mercenaries, they had procured the kingship through violence and much bloodshed.
[10] Mirabilia Urbis Romae, a popular medieval guidebook to Rome for the use of Christian pilgrims, mentions that the Greek church of San Basilio should be visited on account of a bronze tablet that had once been affixed to its wall.
In English: "Attached to the wall of [the church of] San Basilio was a large bronze tablet where there was written, in a suitable and conspicuous place, friendship between the Romans and the Jews in the time of Judas Maccabaeus.
[12] Despite the treaty, Rome did not directly militarily intervene in the Maccabean Revolt or the various wars of the early Hasmonean kingdom, nor were they obligated to by the rather flexible terms.
Rather, the treaty was more a matter of proving legitimacy: that the premier power of the world recognized the nascent Jewish movement as a people worthy of their own autonomy and support.
Historian Chris Seeman suggests that this most likely happened c. 113–112 BCE during the reign of John Hyrcanus, and that the Jewish appeal was apparently successful in getting the Seleucids under King Antiochus IX to back down.