As to teaching the Vatican can BAN anyone from teaching if it whats to. Such a ban ONLY affects the Clergy, for example Martin Luther was banned from teaching but since he no longer consider himself under the Vatican it had no affect. If the Bishops does NOT want to follow the Vatican's ruling he does Not have to, but will be treated as a hieratic. Thus Bishops have a dilemma, either submit to Rome, or go on their own. Given the tendency in the Church to lose power if they break with Rome, the Bishops almost always follow whatever the Vatican dictates. They have been exception to this rule, the last one involves several Priests who oppose Vatican II (and a few Bishops). This has been minimized over time, but at least one bishop disregarded Vatican II and was discipled but retained his Bishops and subsequently anointed some Priest (Which the Vatican refuse to accept for the Bishop was forbidden to anoint Priests). These were from the Right Wing of the Church and the Vatican has been trying ot convince them to accept Vatican II or at least minimized the conflict.
The last big split was after Vatican I (1869), they many left-wing leaning Bishops broke with Rome. These allied themselves with another old split, the "Old Catholics" of the Netherlands. for more on them see:
http://en.wikipedia.org/wiki/Old_Catholic_ChurchMore on the Union of Utrecht:
http://en.wikipedia.org/wiki/Utrecht_Unionhttp://www.utrechter-union.org/english/start.htmA conservative group that broke from the Catholic Church:
http://en.wikipedia.org/wiki/Polish_National_Catholic_ChurchI point the above out to show Bishops have broken with Rome and took their Dioceses with them. On the other hand when Rome makes a ruling it is rare for most Bishops NOT to do whatever Romes Requires. Rome depends on this compliance when it makes its ruling, but the Bishops can refuse to accept the ruling, but that refusals is a break with Rome that most Bishops will not do.
Thus when the Vatican bans a Priest, it is his bishops that enforces the ban. The Bishop can refuse, but that means a break with Rome which most bishops will NOT do.
A list of Schism (prior to about 1900, this is from the 1912 Catholic Encyclopedia, now out of Copyright):
http://www.newadvent.org/cathen/13529a.htmHere is a site I found that says Pope Benedict is TO LIBERAL to be Catholic:
http://www.crc-internet.org/Various French (and other Conservative) bishops have rejected Vatican II, and have broke with Rome. Both Rome and the Bishops have tried to avoid the Break, but nether side will give in on the reason for the break. The latest Schism, basically rejected the Catholic Church's acceptance during Vatican II of "Religious Liberty" instead of Religious tolerance:
http://en.wikipedia.org/wiki/Society_of_St._Pius_Xhttp://en.wikipedia.org/wiki/Marcel_Lefebvrehttp://www.sspx.org/miscellaneous/ab_lefebvre_preparing_the_council.htmNow, this split was done by a Bishop who had resign his Bishopacy and been given a Titular Bishops (Named Bishop of a Diocese that no longer exists for various reasons, but is still a "Diocese" that a Bishop can be named, most are for long forgotten dioceses from the last years of the Roman Empire or on Dioceses that were abolished during the Protestant Reformation). The Bishop was later BANNED from consecrating Priests and other bishops, he subsequently consecrated four bishops and was ex-communicated, but his group, the Society of Pius X, kept their wealth for Rome could NOT touch it. That is the key to a Diocese, if it submits to Rome, it gets bless by Rome and is considered part of the Catholic Faith. If a Bishops does NOT follow what Rome tells them to do, Rome can excommunicate them, but that is all. Any property their control is still the Bishops.