In US v. Lee, 455 U.S. 252, the Supreme Court held that
While there is a conflict between the Amish faith and the obligations
imposed by the social security system, not all burdens on religion are
unconstitutional. The state may justify a limitation on religious
liberty by showing that it is essential to accomplish an overriding
There is no principled way, for purposes of this case, to distinguish
between general taxes and those imposed under the Social Security Act.
The tax system could not function if denominations were allowed to
challenge it because tax payments were spent in a manner that violates
their religious belief. Because the broad public interest in
maintaining a sound tax system is of such a high order, religious
belief in conflict with the payment of taxes affords no basis for
resisting the tax.
Since Measure 106 (a constitutional amendment prohibiting such use of state funds) was defeated, this falls within the purview of the legislatures general tax-and-spend privilege. HB 3391, which generally requires insurance providers to cover the cost of an abortion (thus shifting the burden away from the taxpayer), does carve out an exception for religious employers, but the law does require the state to "design a program to provide statewide access to abortion coverage for
Oregon residents enrolled in health benefit plans described in section 2 (7)(e) and (9) of this
2017 Act" and even requires that "If funding is available, take any actions authorized by state law to implement the
program described in subsection (2) of this section", therefore taxpayer funds are used to fund abortions.
The impediment to a religious-freedom argument is that religious freedom is not absolute, it is balanced against "compelling state interests". State funding of abortion comes from the general fund and there is no special "abortion tax" to which a taxpayer can legally object. It is uncontroversial that religious freedom does not exempt one from paying taxes, see for example Tyms-Bey v. Indiana, where the court rules that "the State's compelling interest in a uniform and mandatory taxation system falls into the statutory exception such that RFRA [Religious Freedom Restoration Act] affords no relief to Tyms-Bey".