Answer:
current income.
Explanation:
Permanent tax cuts increase taxpayers' permanent income. Permanent income includes the taxpayers' expected future income.
While one year tax rebates increase taxpayers' current income. Current income includes the taxpayers' current disposable income.
A lot of spending is done through credit, e.g. car loans, mortgages, credit cards, etc. If your permanent income increases, you can purchase much more goods and services since you can take loans to pay for them.