Donald Trump’s decision to intensify US involvement in Afghanistan represents a complete u-turn for the man who once backed troop withdrawal and blasted his White House predecessors for futile missions that were a “complete waste.”

“Why are we continuing to train these Afghanis who then shoot our soldiers in the back? Afghanistan is a complete waste. Time to come home!” Trump tweeted in 2012, criticizing Barack Obama’s policy of gradual withdrawal of US troops from Afghanistan.

Why are we continuing to train these Afghanis who then shoot our soldiers in the back? Afghanistan is a complete waste. Time to come home! — Donald J. Trump (@realDonaldTrump) August 21, 2012

Four years later the multi-billionaire real estate tycoon and former reality TV star is in the White House and backing an even more muscular approach to Afghanistan than Obama did.

On Monday, Trump said that after studying the issue, he had reconsidered his original instinct to pull US forces out of the 16-year war in Afghanistan.

Trump’s new Afghan plan is a complete flip-flop from the advice he once tweeted as a private citizen.

Between 2012 and 2013 Trump’s Twitter tweeted regularly on Afghanistan. “Wasting our money” and a “speedy withdrawal” were two of the common themes expressed.

We should leave Afghanistan immediately. No more wasted lives. If we have to go back in, we go in hard & quick. Rebuild the US first. — Donald J. Trump (@realDonaldTrump) March 1, 2013

Let’s get out of Afghanistan. Our troops are being killed by the Afghanis we train and we waste billions there. Nonsense! Rebuild the USA. — Donald J. Trump (@realDonaldTrump) January 11, 2013

I agree with Pres. Obama on Afghanistan. We should have a speedy withdrawal. Why should we keep wasting our money -- rebuild the U.S.! — Donald J. Trump (@realDonaldTrump) January 14, 2013

“We have wasted an enormous amount of blood and treasure in Afghanistan. Their government has zero appreciation. Let's get out!” he said.

We have wasted an enormous amount of blood and treasure in Afghanistan. Their government has zero appreciation. Let's get out! — Donald J. Trump (@realDonaldTrump) November 21, 2013

In 2015, during his election campaign, Trump said of an attack in Afghanistan in which US troops were killed: “We are being led to the slaughter!”

A suicide bomber has just killed U.S. troops in Afghanistan. When will our leaders get tough and smart. We are being led to slaughter! — Donald J. Trump (@realDonaldTrump) December 21, 2015

Trump has not said how many troops he would commit or how he would judge success as he laid out his military plans for Afghanistan during an address to the nation from Fort Myer military base in Arlington, Virginia.

A resurgent Taliban controls greater areas of the country than at any time in the 16-year war with the group launching a bloody offensive in recent months. Islamic State (IS, formerly ISIS/ISIL) has also gained control of swathes of the war-torn country.

In his latest speech, Trump announcing no deadlines would be set for withdrawing troops from Afghanistan, with no “rapid exit” from the war.

READ MORE: No troop pullout, threats to Pakistan in Trump speech on new Afghanistan strategy (VIDEO)