Dozens of Texas Democrats have secretly left the state in a dramatic effort to stop Republicans from holding a vote that could determine the balance of power in the US Congress.

Republican Governor Greg Abbot has issued orders that they be arrested on sight - and fined $500 a day. He has also threatened to expel them from office.

The Democrats left because at least two-thirds of the 150-member legislative body must be present to proceed with a vote on re-drawing Texas's electoral map. The plan would create five more Republican-leaning seats in the US House of Representatives.

This high stakes battle may seem both bizarre and confusing – but it is one that could spread to other states in advance of next year's national midterm elections. At its heart, it's a bare-knuckle fight over political power, who can wield it most effectively and who can keep it.

The US House of Representatives is made up of 435 legislators who are elected every two years. They represent districts with boundaries determined in processes set by their state governments.