President Donald Trump is one step closer to achieving his first major legislative victory, with Senate Republicans voting to open debate on a tax bill that would benefit the wealthiest Americans. 

A final Senate vote on the measure is expected later this week following 20 hours of debate and a series of amendment votes – when senators will have the opportunity to propose changes to the legislation.

Before leaving Washington for Thanksgiving, multiple Republicans had expressed concerns about the legislation and its effects. But this week, many of those sceptics seem to be warming to the proposal and have made comments suggesting they may vote ‘yes’.

The Senate’s Republican leadership is likely to cut deals and make promises to its party members to ensure that they support the bill. If the measure passes, the Senate and House of Representatives would need to reconcile their two tax plans before Mr Trump could sign a final version into law. 

Ahead of the Senate vote on Wednesday, Mr Trump in a speech again labelled the tax bill as a win for middle-class families. 

But while the Senate plan would be a windfall for the rich, it is expected to have mixed effects on medium and low-income families.

“This week’s vote can be the beginning of the next great chapter for the American worker,” Mr Trump said, also asserting that it would allow people to keep more of their paychecks. 

The Senate tax bill would cut the corporate tax rate from 35 per cent to 20 per cent, while also repealing Obamacare’s requirement that most people have health insurance – a proposal that would lead to 13m people losing their health insurance over the next decade, according to the nonpartisan Congressional Budget Office. 

Republicans hold 52 seats in the 100-member Senate, and they can afford to lose no more than two of their members’ votes. Democrats are expected to remain united in their opposition to the bill.

In the event of a tie, Vice President Mike Pence would cast the deciding vote.