"I love it."

That's how Donald Trump Jr. responded, we now know, to an email last year offering dirt on Hillary Clinton from the Russian government.

What I love is the defense of this attempt by senior Trump campaign officials to receive Russian help in the election. As my colleagues John Wagner and Rosalind Helderman report, presidential advisers are explaining away the meeting with the Russian lawyer as a "rookie mistake" by an "unsophisticated" campaign.

"Rookie mistake": the all-purpose defense of the Trump White House.

When President Trump failed to support NATO's collective-defense promise, Senate Majority Leader Mitch McConnell (R-Ky.) called it "a rookie mistake." After revelations of Trump's meddling in the FBI's Russia probe, House Speaker Paul D. Ryan (R-Wis.) explained that Trump is "new at this." The rookie-error explanation has been employed to describe Trump's firing of FBI Director James B. Comey, his handling of health care and his legislative approach.

There have been enough rookie errors to send this whole team back to Double-A ball. The longer this goes on, the less it looks like growing pains than incompetence and mismanagement aggravated by nepotism and dishonesty.

The president, representing the United States at the Group of 20 summit in Germany, tweets that "everyone" at the world conference is talking about why Clinton campaign chairman John Podesta wouldn't give DNC servers to law enforcement. Trump erroneously claims the CIA sought the server. Podesta, who had no authority over the DNC, urges "our whack job" president to "get a grip."

Trump gives a speech in Warsaw contradicting an earlier speech he gave in Riyadh, Saudi Arabia. While in Poland, he publicly disparages U.S. intelligence agencies.

The president meets with Chinese President Xi Jinping and the White House press release identifies his country as "the Republic of China" — that is, China's foe Taiwan.

Trump meets with Vladimir Putin and tweets that he "discussed forming an impenetrable Cyber Security unit" with Putin. Twelve hours later, Trump tweets that such a "Cyber Security unit" can't happen.

Secretary of State Rex Tillerson tells reporters that Trump discussed sanctions with Putin. Trump tweets the next day: "Sanctions were not discussed."

Trump's voter-fraud commission requests voter files and is roundly rejected by Democratic and Republican state officials alike; the Mississippi secretary of state, a Republican, tells the commission to "go jump in the Gulf of Mexico."

In spite of Trump's vow that a North Korean missile capable of reaching the United States "won't happen," North Korea tests an ICBM. Trump calls this "very, very bad behavior."

The president tweets that a cable-news host, Mika Brzezinski, was "bleeding badly from a face-lift" when he met her. Sen. Ben Sasse (R-Neb.) responds: "Please just stop."

Trump follows this by tweeting a mock professional wrestling video of him pummeling "Fraud News CNN."

The Post's David Fahrenthold reports that fake Time magazine covers featuring Trump were on display in at least five of Trump's clubs.

The president, who had implied he had tapes of his talks with Comey, tweets that there are no such tapes. Lawmakers, calling the president's word insufficient, threaten to subpoena the tapes.

Trump claims the Senate health care bill "is working along very well." Republican leaders soon abandon plans to vote on the bill.

The White House issues a statement threatening to bomb the Syrian regime. Both the intelligence community and the Pentagon appear to be caught off guard.

Eight months after the election, Trump tweets: "Hillary Clinton colluded with the Democratic Party in order to beat Crazy Bernie Sanders."

Now, after months of Trump denials of Russia contacts, comes proof of a Russia meeting with Donald Jr., Jared Kushner and then-campaign chairman Paul J. Manafort during the campaign. Among Junior's conflicting explanations: It was OK because the Russian didn't produce good dirt on Clinton.

And these are just some of the misfires.

They aren't rookie mistakes. This is a team that never should have taken the field.

— Follow Dana Milbank on Twitter, @Milbank.