Sen. Rand Paul (R-KY) chats with the press as he returns to the White House after a round of golf with President Donald Trump, in Washington, U.S., October 15, 2017. REUTERS/Mike Theiler

WASHINGTON (Reuters) - Republican Senator Rand Paul on Tuesday threatened to vote ‘no’ on a budget resolution Republican leaders aim to bring up for a vote this week unless they decide to stick with spending caps, potentially putting the party’s tax cut plans at risk.

“I have told the White House and (Republican) leaders that if they simply stick to their own caps, the rest of the budget is fine and I’ll vote yes,” Paul wrote on Twitter. “It is a simple, but important, change they could easily make. The ball is in their court.”

Republican leaders can afford to lose only two Republican votes on the budget plan, which would pave the way for large-scale tax cuts, if Democrats remain united in opposition. With Senator Thad Cochran out of town for health reasons, a defection by Paul would leave the vote on a razor’s edge.