George W Bush has spoken out against “disturbing” rhetoric being used in the national immigration debate triggered by Donald Trump.

The former Republican president said the ongoing debate “undermines the goodness that is America”, and fails to “recognise the valuable contributions that immigrants make to our society”.

Mr Bush was speaking on Thursday in a conversation with former President Bill Clinton at the Clinton Presidential Centre in Little Rock, Arkansas, when he decidedly rejected the position of many conservative officials in Mr Trump’s administration.

Under Mr Trump, the US enacted a “zero tolerance” policy which caused the systemic separation of under 3,000 migrant children from their families at the US-Mexico border.

The president has also repeatedly used derogatory terms when referring to immigrants, describing Mexican migrants as “rapists” and “criminals” and claiming the country is becoming “infested” by crime and gangs.

Mr Bush said comments like that erode the public’s support and commitment to immigration, since they’re being made to believe that “the system is broken”.

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“It obscures the fact — the rhetoric does — that the system is broken and needs to be fixed,” he continued.

The former president hasn’t spoken out often against Mr Trump or his controversial rhetoric — certainly, he’s been less vocal than former President Barack Obama. Mr Bush’s wife spoke out against the separation of families at the border, however, along with every other living first lady, including Melania Trump.

“I live in a border state,” she wrote in an article for the Washington Post. ’I appreciate the need to enforce and protect our international boundaries, but this zero-tolerance policy is cruel. It is immoral. And it breaks my heart.”

Mr Trump signed an executive order walking back his policy of separating families, as his administration works to reunite the migrant children with their parents.