Chief Justice John Roberts's surprise decision to support "Obamacare" has occasioned much ridiculous prattle about its supposed underlying motive: to preserve the Supreme Court's credibility as a nonpartisan body. As though it had ever had such a thing. In point of fact, what political scientist Michael Parenti appropriately refers to as "The Supremely Political Court" (see his superb, "Democracy For The Few," now in its ninth edition), has always been highly partisan on behalf of the wealthy and against the working class.
Many of the early Supreme Court justices, for example, including John Marshall, were slaveholders, and repeatedly went along with the legal fiction that black people were simply farm animals. Right up until the Civil War they reasoned that, whether slave or free, blacks were a "subordinate and inferior class of beings" without constitutional rights, and that Congress had no power to exclude slave masters and their chattel from the territories. Meanwhile, the Court did not challenge the Constitution in defining slaves as three-fifths human for the purpose of enhancing their masters' voting power. For sheer cynicism, it's difficult to improve on that.
The "non-partisan" Court has also seen fit to give away huge portions of the country to private speculators, subsidize private industry in direct violation of supposed "free market" requirements, set up commissions that fixed prices and interest rates for banks and manufacturers, dispatch the Marines to secure corporate interests abroad, imprison dissenters who denounced war and capitalism, deport immigrant political organizers without a trial, and use the United States Army to shoot down workers in the streets. Ideological differences between Democrats and Republicans did nothing to prevent any of this.
On the other hand, when dissenting popular movements got strong enough to make the federal or state governments limit the length of the working day, establish a minimum wage and workplace safety standards, guarantee the safety of consumer products, protect and preserve collective bargaining rights, then the Supreme Court did an about face and said the U.S. is a government of limited powers that has no constitutional authority to tamper with property rights and the "free market" by denying "substantive due process" and "freedom of contract." "Substantive due process" is a highly partisan invention that exists nowhere in the Constitution. It has permitted the court to declare laws unconstitutional if and when they interfere with the "right" of corporations and wealthy investors to accumulate capital and wield the power that comes with it. This effectively nullifies democracy, since any effort to promote the general welfare on behalf of the large majority of the population that works for a living can and is construed as an illegitimate denial of property rights and substantive due process. [And the Court regularly overlooks the fact that rights inhere in persons, not property.]
Incredibly, the Court has interpreted the 14th Amendment, passed to establish citizenship for ex-slaves, as giving the rights of personhood to corporations, as though the immense, decades-long struggle of abolitionists to rid the country of the detested practice of slavery had been motivated by a "humanitarian" desire to guarantee business conglomerates the freedom to re-invent slavery by other means. In any event, by 1920, the legal fiction of corporate personhood had struck down hundreds of labor laws that had been approved by state legislatures to ease the brutal conditions workers of that era were forced to endure. Between 1880 and 1931 the courts issued more than 1800 injunctions against labor strikes. Partisan? You bet.
When Congress banned child labor, the Court ruled it an unconstitutional usurpation of states rights under the Tenth Amendment, which says: "The Powers not delegated to the United States by this Constitution, nor prohibited by it to the States, are reserved to the States respectively or to the people." On the other hand, when the states passed social welfare laws, the Court found them a violation of "substantive due process" under the 14th Amendment. In short, the Tenth Amendment has been used to suppress efforts to promote the general welfare initiated under the Fourteenth Amendment, and the Fourteenth Amendment has been used to stop progressive reform under the Tenth Amendment.
It's hard to get more partisan than that.