House Republican leaders on Monday night unveiled their plan to repeal and replace—or at least modify—the Affordable Care Act, and the bill is drawing negative reviews from U.S. Sen. Rand Paul.

Paul (R–Ken.) took to Twitter and made an appearance on Fox News on Tuesday morning to slam the House GOP health care bill and predict its demise.

"This is Obamacare light. It will not pass. Conservatives are not going to take it," Paul told Fox & Friends. He said the bill will "do nothing" to bring health care costs down or to restrict the steady rise of premiums.

On Twitter, the libertarian-ish senator offered a beat-by-beat takedown of the House Republican bill, attacking it for keeping several elements of the Affordable Care Act intact, including subsidies for buying insurance (which would become a refundable tax credit in the House GOP plan) and the so-called "Cadillac Tax" on top notch insurance plans (that 40 percent tax on employer-sponsored health care plans worth more than $10,000 is supposed to take effect in 2020, but would be delayed until 2025 in the House GOP plan).

"We should be stopping mandates, taxes, and entitlements, not keeping them," Paul tweeted.

Paul was critical of the House GOP health care effort even before the bill was published. Last week, he led reporters on a search for the health care bill, crossing from the Senate side of the Capitol to the basement room on the House side of the complex where the bill supposedly was being drafted. He was turned away at the door by a House Republican staffer.

When a draft version of the bill leaked on Friday, Paul called the proposed tax credits "a new entitlement program." The tax credits are shaping up to the be the most controversial part of the bill for many conservative members of Congress (read Peter Suderman's analysis of the tax credits and the rest of the bill here).

Paul was first elected to the U.S. Senate in 2010, as part of a national wave of conservative and libertarian-minded Republicans who built their campaigns around opposition to the Affordable Care Act. Paul and Rep. Mark Meadows (R-North Carolina) stressed that history in a joint op-ed published Tuesday at Fox News.

"Republicans across America ran on repealing the Big Government takeover of our health care system that is ObamaCare. Opposition to ObamaCare helped the GOP win the House in 2010, the Senate in 2014, and the White House in 2016. Repealing ObamaCare has been a key facet of all our recent victories," they wrote.

Paul and Meadows argue that the Affordable Care Act should be repealed, in full, before a replacement bill is passed. The House Republican plan is an attempt to repeal some parts of the law while replacing others simultaneously.

That approach, Paul and Meadows said, would be tantamount to "ObamaCare provisions dressed up in shiny new GOP-branded clothes" and "would mean the loss of too many conservative votes for passage."