The key here is that you state: we live in a community property state.
In a community property state, your salary is by definition community income. As such, if you file separately, she must claim half of that salary herself. See the IRS publication 555 on Community Property for more details:
Community income is income from:
- Community property;
- Salaries, wages, or pay for services of you, your spouse
(or your registered domestic partner), or both during your
marriage (or registered domestic partnership) while
domiciled in a community property state; and
- Real estate that is treated as community property under
the laws of the state where the property is located.
Wages, earnings, and profits. A spouse's (or your registered domestic partner's) wages, earnings, and net profits from a sole proprietorship are community income and
must be evenly split.
So if you earn $100k, and you file separately, and were domiciled in a community property state, you would report $50k yourself and she would report $50k herself.
The capital gains income might or might not be split, depending on where the property came from originally; if it originated from before the marriage, it might be considered separate income. However, it seems to me like the IRS would be very likely to characterize the particular scheme you envision as violating the separation of property. I would also be concerned that if you did successfully have the property declared as separate, you might lose all of it in the event of a divorce. And of course, if you are gifting her money from your salary after marriage, that money is community income and then property bought with it is community property, unless you come to some legal arrangement otherwise and your state permits that.
The idea you suggest in the OP is not totally off the wall, however; some couples do file separately for roughly the same reason. I still don't think the specific example you show would pass muster, though I am not a tax specialist, but for example if my wife had come into the marriage with $1M in securities, and I was the sole wage earner, that would probably qualify in a non-community property state; she would pay income tax on her capital gains each year at a lower rate (up to the cutoff), and I would pay tax on my salary. See this article by USAA for a high level discussion of that concept.
One other note. Since you're married, your nonworking spouse may still be able to make contributions to an IRA, which would allow you some of the tax avoidance you are craving - and in an IRS-approved manner! The Kay Bailey Hutchinson Spousal IRA limit allows a nonworking spouse to deduct up to the individual limit themselves (in addition to the working spouse doing the same), so long as the spouse earns enough (since, normally, you cannot contribute to an IRA if you have no earned income). This limit may be reduced or eliminated depending on your total income, so you may want to consult a tax professional if you're interested in this.