Sen. Bernie Sanders, I-Vt., predicted that health insurers, drug companies and Wall Street will all oppose his "Medicare for All" bill he plans to introduce Wednesday, but said it's time to treat healthcare as a right, not a privilege.

"Now is the time for Congress to stand with the American people and take on the special interests that dominate health care in the United States," he wrote in a New York Times op-ed. "Now is the time to extend Medicare to everyone."

"Needless to say, there will be huge opposition to this legislation from the powerful special interests that profit from the current wasteful system. The insurance companies, the drug companies and Wall Street will undoubtedly devote a lot of money to lobbying, campaign contributions and television ads to defeat this proposal," he wrote. "But they are on the wrong side of history."

"Guaranteeing health care as a right is important to the American people not just from a moral and financial perspective; it also happens to be what the majority of the American people want," he added.

Sanders said a recent poll said 60 percent of those polled want everyone to have Medicare access.

But Democrats themselves are split on the idea, and several Democrats have warned against the idea.

House Minority Whip Steny Hoyer, D-Md., said Tuesday that expanding Medicare for everyone would lead to "significant administrative and other issues."

Hoyer and House Majority Leader Nancy Pelosi, D-Calif., have said they want to focus instead on protecting Obamacare from GOP efforts to dismantle it.