I don't think its entirely accurate that the church's teachings on BC were just in response to the local laws. Even recent prophets and apostles since 1969 have clearly taught that delaying children and the use of birth control is unacceptable:HiJolly wrote:When the law changed in 1965, the rhetoric began to diminish in the Church, save for the 'conservative' leaders of whom the Apostles pretty much to the man belonged. A few noteable exceptions were David O. McKay, Hugh B. Brown and... uh, and... well. I can't think of any others...
“The world teaches birth control. Tragically, many of our sisters subscribe to its pills and practices when they could easily provide earthly tabernacles for more of our Father's children. We know that every spirit assigned to this earth will come, whether through us or someone else. There are couples in the Church who think they are getting along just fine with their limited families but who will someday suffer the pains of remorse when they meet the spirits that might have been part of their posterity.” - Pres. Ezra Taft Benson, Conference Report, April 1969, p. 12
“Many good people, being influenced by the bold spirit of the times, are now seeking surgery for the wife or the husband so they may avoid pregnancies and comply with the strident voice demanding a reduction of children. It was never easy to bear and rear children, but easy things do not make for growth and development. But loud, blatant voices today shout ‘fewer children’ and offer the Pill, drugs, surgery, and even ugly abortion to accomplish that. Strange the proponents of depopulating the world seem never to have thought of continence!” - Pres. Spencer W. Kimball, Conference Report, April 1971, p. 7
“[W]e declare it is a grievous sin before God to adopt restrictive measures in disobedience to God's divine command from the beginning of time to ‘multiply and replenish the earth.’ Surely those who project such measures to prevent life or to destroy life before or after birth will reap the whirlwind of God's retribution, for God will not be mocked.” - Prophet Harold B. Lee, Conference Report, October 1972, p. 63
“True to form, many of the people who desire to frustrate God's purposes of giving mortal tabernacles to His spirit children through worldwide birth control are the very same people who support the kinds of government that perpetuate famine. They advocate an evil to cure the results of the wickedness they support.” - Pres. Ezra Taft Benson, Teachings of Ezra Taft Benson, p. 539
Even in 1995 General Conference there was this remark by a member of the Seventy:"It is an act of extreme selfishness for a married couple to refuse to have children when they are able to do so.” - Pres. Spencer W. Kimball, Conference Report, April 1979, p. 6
In addition, other contemporaries to the above, such as Apostle Mark E Peterson, Bruce R. McConkie, and Elder Neil A. Maxwell have spoken out strongly against the use of artificial birth control. I am not sure how much stronger one needs to get that than invoking temple wording such as "those who project such measures to prevent life... will reap the whirlwind of God's retribution, for God will not be mocked" and indicating in General Conference that postponing children is equivalent to violating a temple covenant.“Thus we see that in marriage, a husband and wife enter into an order of the priesthood called the new and everlasting covenant of marriage. This covenant includes a willingness to have children and to teach them the gospel. Many problems of the world today are brought about when parents do not accept the responsibilities of this covenant. It is contradictory to this covenant to prevent the birth of children if the parents are in good health.
Thirty-five years ago when I first started practicing medicine, it was a rare thing for a married woman to seek advice about how she could keep from having babies. When I finished practicing medicine, it was a rare thing, except for some faithful Latter-day Saint women, for a married woman to want to have more than one or two children, and some did not want any children. We in the Church must not be caught up in the false doctrines of the world that would cause us to break sacred temple covenants.” - Seventy J. Ballard Washington, April 1995 General Conference
There is plenty of text to indicate that birth control itself and delaying children have been taught in no uncertain terms to be against God's plan. Sure, Pres. Hinckley made no comments about it. But that doesn't negate the piles upon piles of quotes from other church leaders before him (as well as some comments during his tenure as prophet).
)
) 
