The inalienable right to life of every innocent human individual is a constitutive element of a civil society and its legislation:
"The inalienable rights of the person must be recognized and respected by civil society and the political authority.
These human rights depend neither on single individuals nor on parents; nor do they represent a concession made by society and the state; they belong to human nature and are inherent in the person by virtue of the creative act from which the person took his origin.
Among such fundamental rights one should mention in this regard every human being's right to life and physical integrity from the moment of conception until death
"The moment a positive law deprives a category of human beings of the protection which civil legislation ought to accord them, the state is denying the equality of all before the law.
When the state does not place its power at the service of the rights of each citizen, and in particular of the more vulnerable, the very foundations of a state based on law are undermined....
As a consequence of the respect and protection which must be ensured for the unborn child from the moment of conception, the law must provide appropriate penal sanctions for every deliberate violation of the child's rights.
This seems to imply that a Catholic must support making abortion illegal, at least to be in good standing with the Catholic Church. Of course you can take a both and approach. I don't think Catholics are obliged not to support a social safety net for pregnant women. You can do that, while also supporting making abortion illegal.