Whether Mr. Trump knows it or not, nuclear weapons policy has a meticulous language all its own, meant to signal clearly to allies and adversaries. But his words fall outside that language, creating several possible interpretations with a wide range of meanings and ramifications for the world — as well as an uncertainty that is itself destabilizing, analysts warn.

Here is what he might have meant, translated and explained:

The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes

Could be read as …

● Modernize existing nuclear forces, in line with but upgrading President Obama’s plan

or ...

● Expand qualitative nuclear capability by developing faster or more powerful delivery systems, like cruise missiles

or ...

● Deploy existing weapons systems closer to adversaries, for example in Eastern Europe

Why It Matters

There is little record of the United States using “strength” as a nuclear metric. In the most modest reading, “modernization plus” would increase, without substantially altering, Mr. Obama’s plan to update the nuclear arsenal, projected to cost $1 trillion.

Any increase in qualitative capability — such as the speed of nuclear-capable bombers or the number of missiles that are forward-deployed — would reassure allies who are under nuclear protection, like South Korea. But it would all but force Russia and China to try to match those improvements. Russia, for instance, might deploy more nuclear-capable systems to Kaliningrad, the Russian enclave bordering Poland. China might reduce its response time, for example, by preloading warheads on missiles.

This arms race would increase the number of scenarios that could lead to nuclear conflict. It would also reduce the response time in any crisis, exacerbating the risk of miscalculation.

The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes

Could be read as …

● Move some warheads from reserve stockpiles to active deployment

or ...

● Build and deploy new warheads

or ...

● Build new warheads, but immediately stockpile them

Why It Matters

Any increase would trigger an arms race with Russia, which sees parity with the United States as essential for its security, and with China. It would effectively kill New Start, the treaty between the United States and Russia that capped nuclear deployments and mandated regular inspections. And it would undercut efforts to curb nuclear weapon development in India, Pakistan and North Korea, which are premised on maintaining the global status quo.

The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes

Could be read as …

● The number and yield of nuclear warheads

or ...

● The speed, stealthiness, range or other attributes of weapons that deliver the warheads

or ...

● Both

Why It Matters

A straight reading of this language suggests Mr. Trump is promising both an increase in the number of deployed warheads and the qualitative capability of weapons systems that deliver them. But his unconventional language and lack of policy experience leave doubt as to his intention. Either increase would most likely cost billions of dollars.

The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes

Could be read as …

● As long as I want

or ...

● As long as is necessary to maintain the status quo

or ...

● Until certain foreign states fulfill certain conditions

Why It Matters

Vipin Narang, a political scientist at the Massachusetts Institute of Technology, said Mr. Trump’s phrase “puts the onus on the world” to change its nuclear policies first. This premises Mr. Trump’s nuclear policy as designed to coerce other states to take action, but leaves enough room that he can continue this policy “until pigs fly,” Mr. Narang said. This forces other states to guess at the quid pro quo, without knowing for sure whether America would respond in kind.

The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes

Could be read as …

● All nuclear weapons states

or ...

● Nuclear competitors, namely Russia and China

or ...

● Russia alone

Why It Matters

Vladimir V. Putin, the Russian president and a source of fascination for Mr. Trump, had promised to upgrade Russian nuclear capabilities in a speech just hours earlier. Mr. Trump may be trying to tell Mr. Putin that the United States will match any Russian upgrade. This message may also be intended for China, which Mr. Trump has promised to challenge. Or it may be an effort to coerce all nuclear powers into accepting some global aim.

The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes

Could be read as …

● Avoid any escalation that might disturb the global status quo

or ...

● Accept American nuclear primacy

or ...

● Agree to global nuclear disarmament

Why It Matters

This point, Mr. Trump’s desired outcome, is the least clear. The first goal would maintain longstanding policy. The second, far more aggressive goal would seek to outstrip Russia’s relative parity with the United States. The third would follow both Mr. Obama and Ronald Reagan. But Mr. Narang and Joshua H. Pollack, of the James Martin Center for Nonproliferation Studies, both emphasize that the first half of Mr. Trump’s post promises a strategy that would undercut all three of these goals, instead likely provoking an arms race.

Taken in full, Mr. Trump’s post conveys a range of possible meanings. At one end of that spectrum, it could be read as essentially repeating a central line from Mr. Obama’s 2009 speech, in Prague, setting out American nuclear policy. At the other end, it could be read as unintentionally echoing a recent North Korean statement of nuclear policy.