In a speech regarding the US approach to the 16-year war in Afghanistan, Donald Trump said he wants to keep the number of additional troops being sent a secret but that is likely not going to happen.

He said it was part of the plan to remain unpredictable to the Taliban, who are currently holding territory in various parts of Afghanistan.

“America’s enemies must never know our plans or believe they can wait us out. I will not say when we are going to attack, but attack we will,” Mr Trump declared in front of a mostly military crowd at Fort Meyer in Arlington, Virginia.

But, it appears to be more for politics than security according to Asha Castleberry, an Adjunct Fellow at the American Security Project, who said it would not have mattered to US generals whether the number of troops was revealed or not.

Ms Castleberry told The Independent that the President’s decision whether to reveal troop level numbers does not hurt the military, “it’s more optics”.

The President may have appeared 'tougher' on security to his American security-conscious base and those who worried he would not have the capacity to listen to the several military leaders in his Cabinet.

“It's a tactic to throw them off. What counts is what they see on the ground and what's going to stop the Taliban in Southern Afghanistan,” she said.

It is the President’s discretion to keep troop numbers secret, however he still has to make a budget request to Congress to cover the cost of these additional troops.

Based on the amount of money requested, an estimated number of troops could be guessed according to Matthew Vallone, Director of Research at Washington-based at aerospace and defence consulting firm Avascent.

Mr Vallone told The Independent that since the budget submitted in May this coming fiscal year “does not include funding for additional forces in Afghanistan, the administration will need to submit a supplemental request to Congress.”

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“That will give us some indication as to what he’s requesting, but he could roll up additional items into a request if he so desired,” Mr Vallone said.

However, the appropriations process would most certainly reveal the number of troops if a member of Congress or aide does not do it first.

“Congress tends to guard very closely its power of the purse,” Mr Vallone explained.

He noted that there will be an itemised list of spending in the Congressional appropriations process that will delineate between personnel and equipment costs.

This is not just true for the regular budget, but also supplemental requests such as what Mr Trump will have to submit for the troop surge.

The approximate cost $1.2 million (£936,000) per soldier per year deployed.

According to the non-partisan Center for Strategic and Budgetary Assessments, the cost is roughly $1.4 million (£1.1 million), while the Defence Department has quoted a figure of $850,000 (£663,000).

Mr Trump could also declare that sharing the number of troops would pose a national security risk, though Mr Vallone said that was unlikely to happen and if it does, be “sustainable” in an administration full of leaks.

Ms Castleberry, an Army veteran herself, thinks this latest surge is not a bad idea. She too worries about the "vacuum" created in Iraq for Isis to take a stronghold, replicating itself in Afghanistan.

Having a larger military force in South Asia would give the Afghan Security Forces the “confidence,” training, and air power support to fight the Taliban, she explained.

But, she also said this strategy and troop surge is no different than what Presidents George W Bush and Barack Obama had done - just that they chose to communicate to the American people what was being done with their tax dollars.

Ms Castleberry does see the advantage of a “ground-driven” approach, adding that Washington should not be dictating what happens in the field.

“Conditions on the ground -- not arbitrary timetables -- will guide our strategy from now on,” Mr Trump said in the speech, but without a timeline, or “end state,” some worry that the war will continue as it has done for much of the last 16 years.

“We can't just use military to bring peace and security,” there has to be a diplomatic component too, Ms Castleberry argued.

That is another issue which could be revealed by looking at the appropriations budget breakdown is a restoration of diplomatic budget cuts, as well.

Mr Trump has previously thanked Russian Vladimir Putin for expelling US diplomats since it would save the US money.

He has repeatedly said he would his administration would reduce wasteful spending and in his federal budget proposal there are dramatic cuts to the State Department, approximately 26 per cent.

Mr Vallone said he is “curious as to how some of the commitments made [during the speech] to support Afghanistan will square” with the proposed diplomatic cuts.

“He's gutting the State Department, we need that in place to reconstitute the area and interact with Afghan people,” Ms Castleberry warned.

She noted the President has already closed the State Department office responsible for Afghanistan and Pakistan diplomacy.

Donald Trump says no 'blank cheque' for Afghanistan

Mr Trump said the US would not be “nation-building” in Afghanistan, but in a contradicting statement said there would also be economic development in the country through US help.

The two do not appear to be mutually exclusive and involve both the military and the State Department’s Agency for International Development (USAID).

Mr Vallone said there is a possibility some of the diplomatic cuts could be restored through the supplemental budget request for the troop surge.

Not explicitly revealing the number of troops and not being able to nail down an exact figure per troop could somewhat obscure recovery of some diplomatic functions in the appropriations breakdown.

The White House nor State Department have responded as yet to a request for comment on if diplomatic functions could be restored through the troop surge budget request.

Mr Trump also called on India, Pakistan, and North Atlantic Treaty Organisation (Nato) allies to “do more”.

He specifically called on Nato members to also send more troops as part of the military alliance.

Heather Conley, Director of the Europe Program at the Center for Strategic and International Studies told The Independent that it is safe to “assume that Pentagon officials are sharing their anticipated force posture with select Nato allies.”

However, she does not think that Nato allies will actually send more troops simply because Mr Trump has requested them to do so.

This “new” strategy on South Asia Mr Trump has been touting is not so “new” and Ms Conley thinks Nato allies will just re-state their current commitment to the war.

She said it does not “directly” have to do with Mr Trump’s much-delayed, explicit commitment to Article 5 of Nato - which states that an attack on member is an attack on all of them.

However, “it has more to do with the challenge of European political leaders appearing to publicly support a deeply unpopular US president combined with the uncertainty of US policy in the region.”

These leaders are also facing increased security challenges from Russia and the African continent as well.

Mr Trump also said during his speech that “a wound inflicted upon a single member of our community is a wound inflicted upon us all,” in an apparent reference to the violence in Charlottesville when neo-Nazi, Klu Klux Klan, and other white supremacists clashed with counter-protesters.

However, Ms Conley said that the statement showed his “lack of understanding” of why it was so important for the US to reaffirm Article 5.

Mr Trump did not do so in a speech as he stood in front of a piece of the Twin Towers, a Nato Headquarters memorial to the alliance first and only invocation of Article 5.