Isaac Newton's third law of motion states that for every action there is an equal and opposite reaction.
People immersed in the abortion debate have found that to be true this year. It started with a standing ovation in the New York Senate in January when lawmakers passed that state's Reproductive Health Act, which basically legalizes abortion up to about the time of a child's birth.
You can argue over what exactly the law says, but it would be hard to argue that it and the standing ovation didn't give pro-life people the energy to take more advantage of the political situation in Washington, D.C., and state capitols. And that even goes back to the personality of President Donald Trump.
People holding to the pro-choice position have had the upper hand for years. Although Roe v. Wade has been modified by subsequent decisions since it was handed down in 1973, it remains the benchmark for the idea that somehow, somewhere, the Constitution's implied right to privacy includes the right of a woman to terminate a pregnancy. Abortion moved from being a state matter to a federal one.
And what was supposed to be "safe, legal and rare" became commonplace to the point of being subsidized by Congress. One rule of economics is that if you subsidize something, you get more of it. Which we did.
In theory, Republican lawmakers would be more likely to support the pro-life position. Despite their campaign speeches, few ever attempted to change anything. Too many Republicans in Congress appeared to enjoy being in compliant minority, even when they were the majority.
But then came Donald Trump. Rather than roll over and play dead for Democrats, Trump relished the idea and opportunity to fight back. That appealed to millions of pro-lifers who were tired of being told to sit down and shut up.
What happened with the Covington Catholic High School student who was set upon by national media and social media after he was falsely accused of instigating a confrontation gave conservative and pro-life people another reason to push back - that equal and opposite reaction.
Pro-life people have come around to the necessity of using language to frame their arguments. For years pro-choice people have shied away from the word "abortion," preferring to redefine it as "women's health" or "reproductive rights," as though the fetus had no rights or no standing in the argument.
Instead of referring to a "fetus," which comes from the Latin word for "offspring," pro-lifers are using the words "preborn" or "unborn" to refer to the child in the womb. The use of the word is growing and is useful in reinforcing the beliefs of people in the pro-life movement.
They are also using terms such as "post-birth abortion" to describe the legislation in New York and a similar proposal in Virginia that went nowhere.
Heartbeat bills (another use of language to sell an idea) have been enacted and signed in Ohio, Alabama and Georgia. They're getting most of the attention, but several other states are considering them or have considered them.
Meanwhile, 10 states have provisions in their constitutions that protect the right to an abortion.
Ultimately, it will come down to whether the U.S. Supreme Court decides to hear the appeals to the heartbeat bills that will work their ways through the federal judiciary.
Pro-choice started the year on offense. It pushed too hard, and now it is playing defense as pro-life has seized the momentum. The pro-life movement has hope that it hasn't had in a while, so it will be much more difficult for the pro-choice side to intimidate.
Jim Ross is opinion page editor of The Herald-Dispatch. His email is firstname.lastname@example.org.