I decide by comparing after-tax yield.
Vanguard has tax-exempt bond funds with yield fairly close to that of Total Bond Market. At a tax bracket of 25% or higher it could make sense to put bonds in taxable, but use a tax-exempt bond fund. For those not at Vanguard, Vanguard Tax-Exempt Bond ETF ("VTEB") can be purchased like it's common stock.
Many people don't look closely at dividends. Right now, international has higher dividends than the US. Looking on morningstar's website shows VTSAX as having 1.89% TTM yield, while VTIAX has 2.82% yield. Meaning total international is generating almost 1% more in dividends on which you'll be taxed. So before any credits, the situation starts off worse for international. The foreign tax credit has to offset that additional tax (on the higher dividend) first before it can be a benefit. The level of additional tax paperwork can vary with your tax situation. Overall I've decided not to emphasize putting international in my taxable account, but others in different tax situations may feel differently.
Take a second look at tax-exempt bonds, and a closer look at how international's higher yields could cause higher taxes.