By Patricia Zengerle

WASHINGTON (Reuters) - Republican and Democratic U.S. senators blasted President Donald Trump's proposal for a 23 percent cut in the U.S. budget for foreign aid and diplomacy as "insane" and "short-sighted" on Tuesday, and said it would not pass.

"We're not going to approve this budget reduction. It's insane. It makes no sense," said Republican Senator Lindsey Graham, chairman of the Appropriations subcommittee that oversees the State Department and foreign aid budget.

"I don't know who writes these things over in the White House, but they clearly don't understand the value of soft power," the Republican senator, a close Trump ally on many issues, told a subcommittee hearing on the foreign aid budget.

Graham also called the plan "short-sighted" and said the Appropriations panel would restore funding to previous levels, rather than enacting the 23 percent cut Trump proposed earlier this year.

Graham also asked Mark Green, the administrator of the U.S. Agency for International Development, to send Congress a plan for how it would assist Venezuela in case of a change in government in the troubled South American state. [nL1N22C1PL]

The hearing took place on Tuesday against a backdrop of upheaval in Venezuela, where Washington's desire to ship in millions of dollars in foreign aid has been a central theme of the Trump administration's push for a change in government. [nL1N22C07O]

The Senate subcommittee's top Democrat, Senator Patrick Leahy, also opposed the cuts, citing the importance of "soft power" like foreign aid to U.S. influence around the world.

"Our soft power should not be a partisan issue, it should be an American issue and we're going to try to keep it that way," Leahy said at the hearing, at which Green testified on Trump's proposed budget.

Graham asked if Trump's administration had a plan in place to help the Venezuela people if President Nicolas Maduro's government were to fall. Graham suggested that the administration submit an emergency funding request for Venezuela to his committee, including a plan.

"I think most members of this committee would gladly help you with some resources to stabilize Venezuela when Maduro falls, not if. In that regard, we would very much appreciate any advice you give us about what a good response would look like," Graham said.

(Reporting by Patricia Zengerle in Washington; Editing by James Dalgleish)