Democrats have introduced a bill to block Donald Trump from declaring a national emergency to get funds for his border wall.

According to the Restrictions Against Illegitimate Declarations for Emergency Re-Appropriations (RAIDER) Act, "no funds appropriated or otherwise made available prior to the date of the enactment of this Act may be used for the construction of barriers, land acquisition, or any other associated activities on the southern border without specific statutory authorization from Congress."

The timing is no accident.

Trump was forced to concede his demands for border wall funding after a record-breaking 35 day government shutdown which cost the US economy an estimated $11 billion. Now the president has suggested that he may declare a state of emergency during his State of the Union address on Tuesday.

"I don't want to say it," Trump said, "but you'll hear the State of the Union, and then you'll see what happens right after the State of the Union."

Democrats want to block the president from using emergency funds to build his wall.

"President Trump shouldn’t be raiding essential funding from American recovering from natural disasters, or from our critical military infrastructure to pay for his vanity project," said Nevada Senator Catherine Cortez Masto.

For many, a state of emergency isn't an option.

If Trump does declare a state of emergency, he would be faced with an immediate court challenge. The RAIDER act, supported by more than a dozen Democrats, would block future power grabs by preemptively preventing the president from access to emergency funds.