On August 8, Trump threatened North Korea with "fire and fury like the world has never seen", touching off a war of words between the two governments.
Will the allies keep it low-key, or focus on projecting strength?
The annual exercises have taken on greater significance this year due to the rise in tensions around North Korea's rapid progress in developing nuclear weapons and missiles capable of reaching the USA mainland.
The drills involving tens of thousands of US and South Korean troops are due to begin on Monday. This year, 17,500 members of the USA military and almost 50,000 servicemembers from the South Korean military are taking part.
The president hates the intense criticism that he's faced over failing to immediately denounce the white nationalists and Nazi sympathizers who engaged in violent protests in Charlottesville, Va., that led to the deaths of three people.
Haass summarized three of the only options the United States has when dealing with Pyongyang: acceptance, military intervention, or diplomacy.
There's media speculation that the allies might try to keep this year's drills low-key by not dispatching long-range bombers and other US strategic assets to the region.
"He's absolutely right", said former North Korea nuclear negotiator Joel S. Wit.
The South Koreans appear to be vehemently opposed to the militarization of the crisis and entrusting their security to the unforeseeable strategic intentions of the Trump administration.
Washington is "prepared militarily" to respond, if necessary, he said.
"Our father asked us to render devoted service to our great leader Kim Jong-Un", said Ted Dresnok, who also goes by the Korean name Hong Soon-Chol.
"If North Korea carries out a sixth nuclear weapons test, China will likely cut oil supplies to North Korea".
The posters clearly denounced United Nations sanctions, after the latest round was slapped on North Korea on August 5 following its milestone intercontinental ballistic missile test in July.
The US-South Korean military exercises have exacerbated tensions in the past. The question is how strong it will be.
Dunford noted that Japan and the United States made progress in anti-submarine warfare, integration of ballistic missile defense, exchanges of officers during exercises, and other matters.
North Korea would be "crossing a red line" if it put a nuclear warhead on an intercontinental ballistic missile, South Korea's president said on Thursday, but the United States had promised to seek Seoul's approval before taking any military action.
But others think the North might use the drills as an excuse to conduct another ICBM test or maybe even act on its threat to lob missiles into the waters near Guam.
"There is no such thing as a surgical strike against North Korea", Bruce Bennett, a North Korea expert at the RAND Corporation, said in one of its recent publications.
There are calls in both the United States and South Korea for the allies to pause or downsize the joint military exercises to reduce strain and potentially persuade North Korea into talks to freeze its nuclear program.
Beijing does not have any problem with the current Kim regime and fears the negative consequences of the use of military power by its archrival, the USA, in its backyard.
"Smart military planning means ensuring that exercises do not enflame an already tense situation", Wright said.
In 2005, North Korea reached an agreement with six countries to suspend its nuclear programme in return for diplomatic rewards and energy assistance but the deal later collapsed.
At the so-called "2+2" meeting in Washington, Mattis, US Secretary of State Rex Tillerson and their Japanese counterparts - Japanese Defence Minister Itsunori Onodera and Foreign Minister Taro Kono - also agreed to step up their defence cooperation in the North Korean threat. In response to that exercise, North Korea threatened a "merciless attack".
America's diplomatic and defense chiefs sought Thursday to reinforce the threat of possible USA military action against North Korea after President Donald Trump's top strategist essentially called the commander-in-chief's warnings a bluff.