"legally straightforward" is a correct and usable phrase in written English.
You can use it to describe a legal process that is not especially complicated or difficult to understand. For example: "The legal requirements for setting up a new business are fairly straightforward."
The reason, legally, was straightforward: if Skokie could pass laws to ban speech it hated, then so could towns in Mississippi and Alabama and Georgia pass the same laws to ban speech they hated, namely, blacks and whites marching together for an end to Jim Crow laws.
"It's really very straightforward legally".
If you're American, watching Game of Thrones legally is pretty straightforward.
"Legally, the issue is straightforward," said Michael A. Olivas, a professor of immigration and education law at the University of Houston.
Certifications are relatively straightforward, but are legally required for products to be sold in certain countries.
Marci Hamilton, a law professor and expert in church and state law at the Benjamin N. Cardozo School of Law who has been following the case, said that legally, the case was a straightforward one about "corruption, about the single religious group taking over all political and city functions".
The testing kits themselves are ridiculously straightforward and can be purchased legally online for just a few quid a go.
As one of the most straightforward ways to relocate to Canada legally, Americans are increasingly applying to Canadian universities.
Nearly every state has since reached the right conclusion, that Dreamers who now live here legally should be able to drive legally, too, as a straightforward matter of public safety and common sense.
Its demands were straightforward but bold: allow the church to take possession of the space it had legally purchased.
