As Republicans have now assumed control of Congress, they face a defining challenge — proving they are serious about fiscal responsibility. For years, the party has campaigned on reducing deficits and curbing wasteful spending, yet they have been complicit in ballooning the national debt. Now, with the debt exceeding $36 trillion and interest payments becoming the fastest-growing federal expense, there is no room for excuses. The GOP must use its majority to restore Congress’ credibility on fiscal discipline, and not exasperate our debt problem even more.

The U.S. economy is at an inflection point. Rising interest rates — the fastest growing portion of the federal budget — make servicing the debt costlier, diverting funds from essential priorities like national defense, infrastructure and economic growth. Both parties have contributed to this crisis, with Republicans historically approving tax cuts without corresponding spending reductions and Democrats pushing for expansive government programs. If Republicans truly believe in limited government and sound financial management, now is the time to act.

This issue is especially critical for Colorado. Our state thrives on a diverse economy, from agriculture and energy to technology and tourism. But runaway federal debt threatens long-term stability. Rising interest rates squeeze small businesses, make homeownership less attainable for working families and could ultimately force cuts to federal investments in infrastructure projects vital to Colorado’s rural and urban communities alike. If Congress fails to rein in spending and reduce the deficit, essential programs that benefit Coloradans could be on the chopping block.

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Over the next two years, the GOP controlled Congress must commit to no new borrowing. That means resisting the urge to pass massive deficit-expanding tax cuts, demanding spending offsets for any new initiatives, and engaging in bipartisan negotiations to address long-term drivers of debt, such as critical entitlement program reforms for Social Security and Medicare. Fiscal responsibility should not be a campaign slogan — it must be a governing principle.

With the GOP’s reconciliation budgets expected to add $3.5 trillion to $4 trillion in the House and billions in the Senate, Republicans must stick to fiscal responsibility to accomplish the president’s goals — not plummet us into more debt. This means committing to no new borrowing to fund the party’s and president’s priorities. And if Republicans are going to extend tax cuts, they must seek out other avenues to take in revenue to cover the cost offsets of re-implementing them. The common misconception is tax cuts can pay for themselves. In 2017, the tax cuts only offset 20% of the revenue loss through growth. If tax cuts are going to be included in a final reconciliation package, Republicans must seek other routes to take in revenue, consider lowering the total cuts to not take from the offset that could instead be paid to cover the debt, and commit to no new borrowing.

Many argue we can simply outgrow our debt through continued economic growth. Though economic growth does lead to a higher revenue income, programs like Social Security are linked to wage growth and grow when the economy does. For us to rely solely on the economy is irresponsible. It would take decades of growth for our economy alone to put the debt on a downward path. We must take decisive action to curb our growing debt.

Democrats should join in this effort to bring fiscal responsibility back to Washington. Though we may not support deficit-financed tax cuts, we do support a commitment to no new borrowing and an honest, realistic approach to offsets. History has shown tax cuts alone do not pay for themselves — at best, they have offset only 20% of lost revenue through growth. If Republicans are serious about fiscal discipline, they must acknowledge that fact and pursue responsible offsets, rather than relying on wishful thinking. Democrats have long advocated for smart budgeting, ensuring we fund essential programs without saddling future generations with more debt. This is an opportunity for both parties to come together, recognize permanent borrowing is unsustainable, and agree on pragmatic solutions that include responsible offsets and spending restraint.

While Republicans have control of Congress and the White House for the next two years, they must prioritize fiscally responsible governance. They can do so by continuing to cut out waste in government spending, considering a pay-as-you-go approach for all funding — where any new spending must be offset by cuts elsewhere — and stabilizing our debt to Gross Domestic Product (GDP), not allowing the debt to balloon anymore.

We now find ourselves at a critical point in the journey toward debt reduction. Republicans have the opportunity to usher fiscal responsibility back to Washington by committing to debt reduction and only paying for things we can afford. I hope they will make the tough decisions and prioritize our debt. Our economic security depends on it.

Mark Udall served in the US House of Representatives from 1999-2009 and in the United States Senate from 2009-2015. He is a member of Colorado Citizen’s Committee on the National Debt.