Is it uncommon for USA presidential candidates to announce Cabinet picks before Election Day?

Question

On Thursday, Marianna Sotomayor from NBC reported that Joe Biden was planning to potentially announce some of his Cabinet nominations before the November election:

NEW: At his second virtual fundraiser today, @JoeBiden announced he's already putting together a transition team to vet cabinet members, brainstorm possible new cabinet positions and add talent throughout departments.

Biden said discussions are underway to see whether several Obama White House offices like technology policy and pandemics should be elevated to cabinet level positions. His transition team would discuss that as well as making a climate change position that goes beyond the EPA.

@JoeBiden also did not rule out announcing some cabinet members before possibly being elected president. He said he “would consider announcing some cabinet members before the election,” but quickly clarified that he hasn’t “made that commitment” yet.

The reporting on this makes me think that this strategy is unusual, is this correct? If so, why?

Answer 1

Picking cabinet members before election day is definitely rare. First, such decisions have no real force. Cabinet members must be approved by Congress, and they cannot be sent to Congress before the President is sworn in, so any name the candidate drops prior to the election is little more than a placeholder for a future choice. Further, choosing cabinet members during the ramp-up to the election would risk muddying the candidate's message. Generally speaking, a candidate wants attention focused on him or herself in an election; bringing in a cabinet pick shifts focus, and creates opportunities to criticize the candidate for any failings of the person he taps.

I suspect Biden is bringing up this issue — just as he went ahead and committed to choosing a woman VP well before the convention — because it's a way of showing he is above the chaotic revolving door of senior officials that has marked the Trump administration. Biden wants to show that he is stable, far-thinking, careful, and transparent, the opposite of the traits that people on both sides of the fence criticize Trump for. It's an interesting political calculation.

Answer 2

It doesn't appear to be normal. A source I found indicates that this is usually done after the election (emphasis mine).

There will be a brief transition period following the election, allowing a new president to select cabinet members and make plans.

Worth noting is that Trump allegedly did it in 2016, though there were questions whether it was even legal. It certainly didn't seem normal:

Trump, who is currently vetting vice-presidential candidates, has already said he will announce his running mate at the convention in mid-July. But sources say the presumptive GOP nominee has also quietly begun reaching out to potential cabinet secretaries, with the possible aim of introducing his future appointments to key administration posts — including Attorney General, Secretary of Defense, Secretary of State, and Treasury Secretary — at the convention.

There’s just one problem: It might be illegal.

The article continues discussing the legality of doing this, most of which isn't relevant to your question. The point is, it definitely seems uncommon.