Taxes do not fund government spending in a modern monetary economy where the government is the monopolist supplier of a fiat currency.
In other words the government does not have a budget constraint in terms of its own money.
The government can afford to build anything it wants as long as the costs are denominated in their own currency.
The constraint is only on the availability of goods and services denominated in that currency available for purchase.
Here is the reason why federal governments crap on so much about a surplus budget being a good thing:
If the non-government sector wishes to save then the government MUST have a Budget Deficit.
Hence, if the Government sector is in surplus then the non-goverment sector must be in deficit - No exceptions because Debits always equal credits under accrual accounting rules.
The reason why both major parties desire to run a surplus budget is because they want the private domestic sector to spend more than they earn.
Reason: For people to spend more than they earn they need to obtain credit -Hello Banks - Hello Bank share prices rising.
Both major parties are unfortunately captured by the financial sector in this country and that is why they seek to run a surplus.
Note also: If governments continually run surpluses then it is IMPOSSIBLE for the non-government sector to save because:
Government surplus = non-government deficit.
If you add an external account to the identity then it gets even worse as Australia has had a current account deficit throughout much of its existence due to the majority of our big players being foreign owned. THis is shown as the net income component in the National Accounts - and another reason why the so called mining boon was only of benefit to a selct few rather than the entire population as the Gina's and Andrews of this country try and tell us.