Sen. Bernie Sanders (I-Vt.) on Monday said Democrats would fight Republican efforts to defund Planned Parenthood, ridiculing the plan as an "obsession" that "has nothing to do with improving healthcare" and everything to do with shutting down abortion providers.

"Republicans in Congress have returned to their old obsession of trying to defund Planned Parenthood. This is outrageous for many reasons," Sanders tweeted. "Abortions are not only legal. They are constitutionally protected, a right which was affirmed again in a Supreme Court ruling last summer," referring to the landmark decision in Whole Woman's Health v. Hellerstedt that found the state of Texas could not place restrictions on abortion access that created an undue burden for woman—considered the biggest reproductive rights case since Roe v. Wade in 1973.

House Speaker Paul Ryan (R-Wis.), who has been leading the charge to overhaul federal healthcare policies, confirmed last Thursday that defunding Planned Parenthood will be included in the Republicans' "reconciliation" bill, which will also repeal the core of the Affordable Care Act (ACA). The bill is expected to be introduced as early as this week.

Reproductive rights groups have been conducting an ongoing campaign of support for the organization, but the urgency of their message was amped up after Ryan's announcement, the denouement of a 15-month long GOP-led investigation into Planned Parenthood that ended with a recommendation to strip the group of federal funding. On Friday, NARAL Pro-Choice America tweeted, "Access to [reproductive health] care is a human right," and urged supporters to call his office.

But Ryan has remained obstinate. He reportedly called security on Planned Parenthood volunteers who had gathered at his office on Friday to deliver 87,000 petitions asking him to protect federal funding for the organization—prompting the creation of the hashtag #PaulRyanSoScared.

The healthcare provider has long been in Republican crosshairs. President-elect Donald Trump's nomination in November of anti-choice Rep. Tom Price (R-Ga.) as health and human services secretary seemed to confirm widespread fears that a newly emboldened defunding campaign would soon come.

Efforts to block federal assistance for the organization are already underway in some states—such as, perhaps unsurprisingly, Texas—where state health officials delivered a final legal notice in December that Title IX funds would be shut off in 30 days. Planned Parenthood president Cecile Richards warned at the time that "if the nation goes the way of Texas, it will be nothing less than a national healthcare disaster."

As Sanders noted Monday, "Planned Parenthood mostly helps low-income people. Four out of five of those who benefit are at or below 150 percent of the poverty line. Women in this country have a right to healthcare [and] a right to control their own bodies. No cuts to Planned Parenthood. We will fight back."