In trumpeting the virtue of balanced budgets, Finance Minister Joe Oliver often seems to be debating a bogeyman. After all, neither of the main opposition parties so far proposes running deficits. But Tuesday's budget – and this may be its most lasting impact – would make it much harder for a Liberal or New Democratic government to keep Ottawa in the black.

By repeatedly shrinking the tax base through (by Mr. Oliver's own count) 180 "tax relief measures" since 2006, the Tories have made it virtually impossible for any government to enact new programs or enhance existing ones without raising taxes or running sustained deficits.

Neither option makes for a very compelling campaign slogan. Most Canadians feel they already hand over enough of their hard-earned income to governments, while the consequences of chronic deficits were recently laid bare in Europe. Before that, Canada had its own brush with a debt crisis when, in the mid-1990s, The Wall Street Journal held us up as fiscal deadbeats.

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"We cannot borrow our way to prosperity, no matter what our opponents might say," Mr. Oliver said on Tuesday as he tabled his first budget. "Ignoring the lessons of history, they would take the well-trod road to economic decline – a journey that will not end well."

The Tories will beat this drum ever louder in the countdown to October's federal election. Despite running up the biggest deficit in Canadian history, betraying their own fiscal instincts during the recession, the Conservatives have managed to claw their way back to black in spite of the curveball that capitalism has thrown at them in the way of cratering crude oil prices.

Mr. Oliver's first budget was the product of an unusually extended period of gestation, necessitated, he said, by volatile oil prices. We now know why he really needed all that extra time. He's come up with a lot of creative choreography in those "New Balance" running shoes.

The $1.4-billion surplus he is forecasting for 2015-16 hinges on a $3-billion reduction in interest charges over the amount projected in November's fiscal update. Even if the lower interest costs materialize – the projection raised eyebrows among some economists – Mr. Oliver has still had to slash Ottawa's reserve for unexpected expenses to $1-billion from $3-billion for the next three years and rely on continued employment insurance surpluses to balance the budget.

It makes no material difference whether Ottawa posts a small deficit or a small surplus. But surplus sounds better on the campaign trail and this election budget aims to make any spending promises the opposition parties make look unworkable without red ink. In that, it largely succeeds.

The NDP says it would reverse Tory cuts to corporate tax rates. And the Liberals might undo the Tory income-splitting plan. But neither move on its own would allow a Liberal or NDP government to undertake significant new spending – on daycare or infrastructure, for example – without running deficits or raising new revenues.

The Tories have barely left themselves with any fiscal room to manoeuvre. Were either (or both) of the opposition parties to form a government after October's vote, they would struggle to make their numbers work. Even the limited goodies Mr. Oliver promised in this budget – cutting the small business tax rate, boosting defence spending, doubling the annual limit on Tax Free Savings Accounts – do not kick in or cost much in the near-term. A new government could not free up much money over the next few years by cancelling them.

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By repeatedly reducing taxes – mostly through politically efficient but economically dubious measures targeted at key voting blocks – the Conservatives have driven federal revenues to their lowest level in 50 years. They now hover at barely 14 per cent of gross domestic product, down from 16 per cent a decade ago and about 18 per cent in the years prior to that.

Since 2010, the Tories have also dramatically cut direct program spending, generating cumulative savings of almost $18-billion. The Parliamentary Budget Officer calls this the most "sustained restraint" since at least the mid-1960s. Federal spending is set to clock in at 12.9 per cent of GDP this year, back to where it had fallen before the recession.

Still, as Mr. Oliver's footwork shows, balancing the books isn't easy – not even for a party that lives to shrink government. Imagine how hard it would be for one that wants to grow it.