The Biden campaign has been lucky most of all, but it’s also been smart, at least smart enough.

To go, as Joe Biden did, from left for dead to sweeping to the nomination and quickly thereafter emerging as the favorite in November is a run of success that would be the envy of any national politician.

It’s easy to consider this a mere accident given the weakness of Biden’s opponents, first a socialist in the Democratic primaries who had a ceiling on his support and now an incumbent president whose ratings have sagged.

The Biden team certainly isn’t going to rewrite any campaign playbooks or dazzle anyone with its brilliance, but it has avoided serious mistakes and demonstrated an understanding of the basic political terrain and its candidate’s strengths.

It hasn’t asked Biden to do anything out of his comfort zone or beyond his capabilities and has been content for President Donald Trump to dominate all the attention, so long as Trump is not advancing his cause, and often setting it back, with all the airtime and headlines.

Above all, the campaign has avoided the most politically perilous ideological excesses throughout. This has required some discipline, given how influential woke Twitter is on the left.

Biden’s theory of the Democratic Party, even if it seemed doubtful at the outset, proved correct — that the center of gravity of the party was still with, as he put it, Obama-Biden Democrats rather than with the avowed socialists and social justice warriors.

Biden hewed to this line when other candidates went the other way. It might seem obvious that endorsing ‘Medicare for All,’ which involves yanking away the private health insurance of more than a 100 million Americans, is foolish and politically indefensible, but several candidates in the Democrat race did it anyway.

He’s steered clear of other pitfalls since locking up the nomination. He’s said he wouldn’t ban fracking. He didn’t endorse defunding the police. He defended the statues of America’s founders.

He’s indisputably slid left. This has been his MO his entire career — to stay smack in the middle of whatever is the consensus position of the Democratic Party at any given time. He’s running on the leftmost platform of any Democratic nominee in a couple of generations, but has tried to soften the edges as much as possible.

As a general matter, nothing he’s said has made much of an impression one way or the other. His campaign knows that it benefits if the election is a referendum on Trump — and is acting accordingly. On the other hand, Trump should know that it hurts him if the election is a referendum on him — yet persists in making it one anyway.

Why should Biden try to take the mic from Trump if the president is using it to feud with Bubba Wallace and Dr. Anthony Fauci’

Not only do these diversions do nothing to dent Biden, they serve to validate the former vice president’s case that the county needs a return to normalcy.

Still, nothing is decided in July. Events took a hand earlier this year in turning a political tail wind for Trump into a stiff head wind. Something unforeseeable could change the dynamic yet again, and better economic conditions could improve the overall atmosphere.

Biden’s record and agenda give Trump targets to shoot at, and he should obviously take every opportunity to make the election, to the extent he can, about the radicalism of the Democratic Party.

Finally, there’s the fact that Biden is an unsteady performer at best. The strictures around COVID-19 have relieved him of the rigors of the typical presidential campaign, but he’s going to have to emerge to participate in a debate or debates in the fall, and no one can rule out some catastrophic failure.

So, Trump can’t be counted out. But the Biden campaign is canny enough that it isn’t going to make it easy for him.

Rich Lowry is on Twitter @RichLowry