President Donald Trump on Tuesday vetoed Congress latest effort to end the national emergency he declared along the southern border with Mexico in order to fund his border wall.

It was the second time the president has been forced to defend his border policies amid frustration from a bipartisan group of lawmakers who say he bypassed Congress in order to get funding to build his long-promised structure. The Senate voted in September to cancel the declaration by a vote of 54-41, but its unlikely the chamber has enough votes to overturn the veto.

Trump vetoed a similar resolution in March , and lawmakers have pledged to vote through such measures every six months, as allowed by law. The president, however, has said the situation along the border remains a national emergency that threatens the well-being of vulnerable populations.

It has empowered my Administrations Government-wide strategy to counter large-scale unlawful migration and to respond to corresponding humanitarian challenges through focused application of every Constitutional and statutory authority at our disposal, Trump wrote in the veto.

He later went on to praise the construction of the wall itself, claiming the emergency declaration has also facilitated the militarys ongoing construction of virtually insurmountable physical barriers along hundreds of miles of our southern border.

The White House issued the veto on Tuesday evening during the fourth Democratic presidential debate .

Trump first declared the national emergency in February , saying his administration planned to divert $3.6 billion in congressionally appropriated funds from the Defense Department to fund construction efforts. The Pentagon said last month that 127 projects around the globe would be delayed due to the transfer, including projects in nearly half of the 50 states.

The declaration has prompted widespread fury from lawmakers and a bevy of lawsuits, but the Supreme Court ruled in Trumps favor in July.

Big WIN for Border Security and the Rule of Law! Trump tweeted at the time.

Trump defended his earlier veto in the announcement on Tuesday, saying he rejected the earlier bill because it was a dangerous resolution that would undermine United States sovereignty and threaten the lives and safety of countless Americans.

It is similarly my duty, in order to protect the safety and security of our Nation, to return S.J. Res. 54 to the Senate without my approval, he wrote.

The president has continued to tout his hard-line policy along the southern border while replacing any officials who stand in his way. Kevin McAleenan, the acting secretary of homeland security, resigned last week after a tumultuous, six-month tenure in the administration.