Estate taxation of joint property
For federal estate tax purposes, when joint tenants are spouses, it doesn't matter who furnished the consideration for the property: the rule is that one-half of the property is included in the gross estate of the first spouse to die. (IRC section 2040(b)).
For Georgia estate tax purposes, the tax is imposed on so much of the property of the decedent’s estate as would be taxable under the Federal estate tax law, including all real and tangible personal property located within the state and all intangible personal property wherever situate.