If your spouse is not a US citizen, a trust may be very helpful.
There are many issues around citizenship, the primary one being, however, that a non-citizen spouse is not entitled to a federal estate tax exemption called, "The Unlimited Marital Deduction."
There are limits on the amount of money you can leave a non-citizen spouse before you are subject to estate tax.
You should consult with a lawyer in the relevant jurisdictions to understand what your rights are and what possible tax consequences there may be.