So, what are the two legs of iron from the image of Daniel 2? I suggest this question is answered in Revelation 13. Most Biblical scholars agree that the beast of Rev 13:1 is Rome. Likewise, they have assigned both legs of Daniel's image to Rome. I propose, instead, that only ONE iron leg represents Rome (the republic, empire and church).

There is a second beast introduced in Revelation 13:11. This beast is generally interpreted to refer to the United States. In opposition to accepted theory, these two beasts co-exist. I intend to show that this second beast represents the other leg of iron. They both share the same Roman civil law, hard as iron.

And the fourth kingdom shall be strong as iron: forasmuch as iron breaketh in pieces and subdueth all things: and as iron that breaketh all these, shall it break in pieces and bruise. Daniel 2:40

The united States started as a republic under common law (innocent like a lamb, Christlike).

And I beheld another beast coming up out of the earth; and he had two horns like a lamb... Revelation 13:11

Common law is a system of freedom. Under common law EVERYTHING is lawful unless it causes someone harm. Roman civil law is the opposite, a system of slavery. Under civil law, NOTHING is legal unless the law permits it. The United States changed from a common law republic (lamblike) to a civil law democracy (speaking as a dragon - another study). The second beast (the U.S. speaking like a dragon) caused an image to be made to the first (Roman) beast that obtained its power from the dragon.

And I beheld another beast coming up out of the earth; ... and he spake as a dragon. Revelation 13:11

The second beast exercised all the power of the first beast and copied the first beast, causing a mirror image to be made to the first beast (image to the first beast). Roman civil law is now essentially universal (worldwide - ALL countries) and all the world wondered after the beast and worshiped its image. (see the rest of Revelation 13).

Two beasts the same, a mirror image, two parallel identical legs.

But, you might protest, the United States came long after the fall of Rome. They can't be contemporary (existing at the same time).

And [the second beast] deceiveth them that dwell on the earth by the means of those miracles which he had power to do in the sight of the beast; saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live. Revelation 13:14

Revelation 13:14 tells us that the first beast, even after receiving a wound did still live. This is AFTER the second beast gets the world to make an image to the first beast (concurrent, not consecutive - AFTER the U.S. transformed into a democracy).

The 2nd beast (the united States) arose in 1776, the 1st beast was wounded (Pope taken captive) in 1798, then its sovereignity restored in 1929. It DID LIVE. Rome has existed as a republic, an empire, and a church. Then it was wounded, and restored. Its restoration occurred just after WW I when the United States was reaching its power zenith. Both co-existed part of their lives.

The belief in the "fall of Rome" has given the first beast great cover to continue exercising its power. Failure to see that the second beast is just a continuation of the power of Rome diverts us from the real issues.

The first beast (Rome) is one leg of Daniel's image and the second beast (the United States) is the other leg. Two identical legs of iron, both ruling the whole world through their Roman civil law of iron until the 2nd coming.