The Iran war might be the end of Congress' war powers. What happened?

Congress will vote this week on whether to authorize President Donald Trump's war in Iran. It may not matter, experts say.

Congress will vote this week on whether to approve President Donald Trump's already in motion war on Iran, in what experts are calling a "tipping point" for the unique congressional power to declare war, eroded for decades by presidents they say have stretched the constitution's bounds.

The Senate will vote on its version of the legislation on March 4, according to Sen. Tim Kaine, one of the Democrats leading the Senate effort. The bipartisan duo of Democratic Rep. Ro Khanna and Republican Rep. Thomas Massie have introduced legislation in the House to force a vote on the Iran war.

"The American people are tired of regime change wars that cost us billions of dollars and risk our lives," Khanna said in a video statement on Feb. 28, hours after Trump launched the war. "Every member of Congress must go on record today."

The Constitution states that only Congress has the power to declare war. But Trump has launched military attacks on seven countries this term, in each case, without a green light from Capitol Hill.

The United States hasn't officially declared war since World War II. But experts say the new war in Iran could be the nail in the coffin, effectively ending Congress' unique constitutional authority to declare war.