This week, Americans will get a very clear view of the two political parties in high-stakes showdowns — and possibly a sobering insight into how corrupted our politics has become.

Republicans are now committed to fierce obstruction. All the high-minded rhetoric about bipartisan cooperation is background static. The clearest proof will play out this week as Senate Minority Leader Mitch McConnell (R-Ky.) leads a filibuster against a bill to lift the debt ceiling so that the United States does not default on the debts it already owes. Default would probably have catastrophic effects on bond markets, credit and the United States’s standing around the world. McConnell risks this because he wants Democrats to take the blame.

McConnell’s obstruction comes as no surprise, but what’s telling is that there are not 10 Republican senators responsible enough to break the filibuster. Virtually without exception, they echo the lie that Democratic spending is the reason the debt ceiling must be lifted. In fact, the raise would cover much of the past debts accumulated when Republicans held power under President Donald Trump. Sustaining the full faith and credit of the United States by empowering the government to pay its debts does not require a profile in courage. Republicans — in unison — are more committed to partisan posturing than to simple patriotic service.

In the face of this, Democrats must demonstrate that they are prepared to govern. This week, the House is slated to vote on a traditional infrastructure bill. It supposedly has bipartisan support, but the Republican House leadership has announced it will whip members to vote “no.” At the same time, intense negotiations go forward on the heart of the president’s “Build Back Better” agenda, packaged in a budget reconciliation bill to avoid a Senate filibuster.

The $3.5 trillion plan contains reforms that enjoy overwhelming public support. In its current form, it improves families’ lives by sustaining the monthly child allowance, investing in daycare, providing universal pre-K and guaranteeing paid family leave. It makes community college tuition free. It extends Medicare to cover hearing, vision and dental expenses. It lowers prescription drug prices to help seniors and save the government over $500 billion. It makes the first serious investments addressing the threat of climate change. And these measures would be paid for largely by raising taxes on the richest and corporations (at or below the rates before the 2017 tax cuts), cracking down on tax avoidance and curbing fossil fuel subsidies. What’s not to like?

The overwhelming majority of Democrats in both Houses support the president’s plan. But with a margin of three votes in the House, and the 50-50 split in the Senate, any one senator or three House members can torpedo the package. Much of the press portray the Democratic conflict as pitting “moderates” against progressives; the former threatening to vote against the reconciliation package; the latter demanding passage of both bills or neither.

But the dissenters are far from “centrists” or “moderates.” They oppose the plan of the president of their own party, a lifelong moderate, who was just elected with a record number of votes. They undermine a plan that has popular support — both for the package and the individual reforms. If anything, the progressives have acted as the moderates, compromising from their initial $6 trillion plan, giving up favored programs to bring the caucus together.

The few dissenters more accurately should be labeled as corporate Democrats. They enjoy lavish support from corporate lobbies mobilized to oppose all tax hikes and reductions in industry subsidies. Their objections are informed by deep pocket interests that pay for their campaigns. For example, Democrats have long campaigned to allow Medicare to negotiate bulk discounts on drugs. Yet the reform was torpedoed in committee by three House Democrats who have hauled in roughly $1.6 million in campaign contributions from the pharmaceutical industry. Joining them is Sen. Kyrsten Sinema (D-Ariz.), another leading recipient of Big Pharma donations.

Or the dissenters could simply be labeled conservative Democrats because the excuses they use to oppose the popular reforms echo conservative mantras. They object to the cost, raising fears about the deficit and about inflation. Yet $3.5 trillion over 10 years constitutes only a 5 percent increase in projected spending. It pales next to the recently expanded Pentagon budget that will cost a whopping $9.7 trillion over 10 years — which these conservative Democrats supported without objection. And most of their major objections concern raising taxes on the rich or corporations or lowering drug prices and ending fossil fuel subsidies, all of which are designed to pay for the program.

Can Democrats unite to pass the president’s popular program? Or will corporate Democrats gut the reforms to protect the moneyed interests that so corrode our politics? All Democrats realize that failure to act will be political suicide. Whether the president and the Democratic leaders get to agreement on a package that can pass may well be a measure less of their skill than of how corrupted our politics have become.