"You shall not murder." -- Exodus 20:13
Hmmm...no exceptions there.
"We hold these truths to be self-evident, that ALL MEN are created equal, that they are endowed by their Creator with certain UNALIENABLE rights, that among these are life, liberty and the pursuit of happiness. That to secure these rights, governments are instituted among men..." -- The Declaration of Independence
No exceptions there.
"We the People of the United States, in Order to...secure the Blessings of Liberty to...our POSTERITY, do ordain and establish this Constitution for the United States of America." -- The Preamble, or Statement of Purpose, of the United States Constitution
The word "posterity" is all-inclusive. No exceptions there.
"NO PERSON shall be deprived of life without due process of law." -- The Fifth Amendment to the United States Constitution
No exceptions.
"NO STATE shall deprive ANY PERSON of life without due process of law; nor deny to ANY PERSON within its jurisdiction the EQUAL PROTECTION of the laws." -- The Fourteenth Amendment to the United States Constitution
That doesn't leave out a single square inch of American jurisdiction, or a single person within it. No exceptions.
So, even if you're right, and it is the "mainstream Republican position," - which is highly doubtful since the GOP platform has contained the Reagan personhood, Fourteenth Amendment plank for the last twenty-seven years - that still doesn't make your position moral, or constitutional, or legal.
"There is no maxim in my opinion which is more liable to be misapplied, and which therefore needs elucidation than the current one that the interest of the majority is the political standard of right and wrong.... In fact it is only reestablishing under another name and a more specious form, force as the measure of right...." James Madison, to James Monroe: