R. Joseph B. Soloveitchik relates the following story about his illustrious grandfather, Reb Chaim, in Halakhic Man, p. 40:
Once R. Hayyim of Brisk was attending a conference of outstanding Torah scholars in St. Petersburg. The item on the agenda was the question of uncircumcised infants--should their names be entered in the official register of the Jewish community. All of the rabbis declared: "It is certainly forbidden to register them, for they are not circumcised." (Through this tactic they hoped to compel the assimilationists to circumcise their sons.) R. Hayyim arose and said: "My masters, please show me the halakhah which states that one who is not circumcised is not a member of the Jewish people. I am aware that a person who is not circumcised may not partakes of the sacrifices or the heave offering, but I am unaware that he is devoid of the holiness belonging to the Jewish people. To be sure, if he comes of age and does not circumcise himself he is liable to excision. However, he who eats blood and he who violates the Sabbath are also liable to excision. Why then do you treat the uncircumcised infant so stringently and the Sabbath violator so leniently? On the contrary, this infant has not as yet sinned at all, except that his father has not fulfilled his obligation." From a political and practical perspective, and as an emergency measure, no doubt the majority was correct. However, on the basis of the pure Halakhah, R. Hayyim was correct. And he would not sacrifice this halakhic truth even for the sake of realizing the noblest of ideas.It is clear from the story that R. Chaim Soloveitchik's contemporaries disagreed with him. Who were they? I don't know, although I recall seeing that R. Avraham of Sochatchov, the Avnei Nezer, disagreed but I cannot seem to find any documentation of it right now. I did find, in Dr. Adam Ferziger's Exclusion and Hierarchy, that many outstanding German Torah scholars disagreed with R. Soloveitchik's position.
1. R. Ya'akov Ettlinger -- p. 92:
In 1843, a number of individuals within the community of Frankfurt am Main demanded to register their newborn sons as Jews despite their unwillingness to have them circumcised. Numerous Orthodox rabbis were asked to author official protests in support of the struggle of the local rabbinate against these individuals. Most of those who responded, including [R. Ya'akov] Ettlinger, rabbi of Altona, demonstrated their basic agreement with the declaration of the chief rabbi of Frankfurt, Solomon Trier: "The father who persists in his sin and contemptuously, with evil intent and renunciation of the Torah, does not allow his son to be circumcised, is a heretic, has left the Jewish people, and is disqualified from giving testimony or taking an oath."2. R. Samson Raphael Hirsh -- pp. 125-126
Beyond demonstrating strong opposition to marriage between Orthodox and non-observant Jews, there were other means by which the Hirschian hierarchy was maintained, such as the criteria for membership in the IRG. According to the by-laws passed in 1875, there were three gradations of Jews. The lowest level comprised those who were uncircumcised or had not circumcised their children... All of the above were declared outcasts and were forbidden membership in the IRG [community].3. R. Azriel Hildesheimer -- pp. 160-161:
In he summer of 1886, [R. Azriel] Hildesheimer was asked whether uncircumcised thirteen-year-olds could be called up to recite the blessing on the Torah in honor of their bar mitzvah. As in the responsum concerning the Halberstadt defectors, Hildesheimer strived to defend a lenient attitude, demonstrating complete sympathy for these children whose "unfortunate" circumstance was caused by their wayward parents and even bringing halakhic arguments to their defense... Surprisingly, however, his analysis of the issue ended with his saying, "Despite all of the above, it appears to be proper to strengthen this orphaned generation by placing within the mouths of the masses the deepest conviction [emunat o-men] that one who des not enter into the holy covenant is not like others who abandon the religion (whom we permit to be called to the Torah)." Although he sympathized with the boy's predicament, broader considerations led him to believe that it might be better not to allow an uncircumcised child to be called up to the Torah.4. R. David Zvi Hoffmann -- p. 182 (from a 1902 article of his):
But it seems to me that in order to fence in the law [le-migdar milta], we should prevent his burial among the other graves, in order to punish the rebels who violated the covenant of Abraham our Father, may he rest in peace, and who do not circumcise their sons, so that they may "hear and be afraid" and will know that by virtue of this [decision not to circumcise their sons] their children will be separated from the seed of Israel completely, and even after death, they will not have burial among the children of Abraham our Father, may he rest in peace.