The Public Education Tax Credit

Public education is an end, not a means. For a democratic nation to thrive, its schools must prepare children not only for success in private life but for participation in public life. It must foster harmonious social relations among the disparate groups in our pluralistic society and ensure universal access to a quality education. Unfortunately, the American school system has long fallen short as a means of fulfilling these purposes. This paper offers a more effective way of delivering on the promise of public education, by ensuring that all families have the means to choose their children's schools from a diverse market of education providers. All education providers -- government, religious, and secular -- can contribute to public education because all can serve the public by educating children. Educational freedom can most effectively be realized through nonrefundable education tax credits -- for both parents' education costs for their own children and taxpayer donations to nonprofit scholarship funds. This paper argues that tax credits enjoy practical, legal, and political advantages over school vouchers. These advantages are even more important for choice programs that target low-income children, as tax credits mitigate some disadvantages inherent to targeted programs. It also contends that broad-based programs are superior to narrowly targeted ones, even when the goal is specifically to serve disadvantaged students. Targeted programs are fundamentally inferior -- in both practical and strategic terms -- to broad-based programs that include the voting middle class. Finally, accountability in education means accountability to parents and taxpayers. Education tax credits afford this accountability without the need for intrusive government regulations that create political and market liabilities for school choice policies. To date, school choice policy has spread and grown only slowly, in part because of inadequate legislation. Existing school choice laws fall short in terms of both market principles and political considerations. Pursuing a policy that follows more closely what works economically and politically should increase the likelihood of long-term legislative success, program success, program survival, and program expansion

Quasi-geostrophic modes in the Earth's fluid core with an outer stably stratified layer

Seismic waves sensitive to the outermost part of the Earth's liquid core seem to be affected by a stably stratified layer at the core-mantle boundary. Such a layer could have an observable signature in both long-term and short-term variations of the magnetic field of the Earth, which are used to probe the flow at the top of the core. Indeed, with the recent SWARM mission, it seems reasonable to be able to identify waves propagating in the core with period of several months, which may play an important role in the large-scale dynamics. In this paper, we characterize the influence of a stratified layer at the top of the core on deep quasi-geostrophic (Rossby) waves. We compute numerically the quasi-geostrophic eigenmodes of a rapidly rotating spherical shell, with a stably stratified layer near the outer boundary. Two simple models of stratification are taken into account, which are scaled with commonly adopted values of the Brunt-V{\"a}is{\"a}l{\"a} frequency in the Earth's core. In the absence of magnetic field, we find that both azimuthal wavelength and frequency of the eigenmodes control their penetration into the stratified layer: the higher the phase speed, the higher the permeability of the stratified layer to the wave motion. We also show that the theory developed by Takehiro and Lister [2001] for thermal convection extends to the whole family of Rossby waves in the core. Adding a magnetic field, the penetrative behaviour of the quasi-geostrophic modes (the so-called fast branch) is insensitive to the imposed magnetic field and only weakly sensitive to the precise shape of the stratification. Based on these results, the large-scale and high frequency modes (1 to 2 month periods) may be detectable in the geomagnetic data measured at the Earth's surface, especially in the equatorial area where the modes can be trapped