Senate Minority Leader Chuck Schumer (D-N.Y.) says a spending deal has never been closer. Senate Majority Leader Mitch McConnell (R-Ky.) says he's optimistic. So why does news of a potential budget bargain between Republicans and Democrats seem too good to be true?

To reverse an old proverb, skepticism in this case is the triumph of experience over hope. In recent months, the battle to keep cash flowing to federal agencies for the fiscal 2018 budget cycle has produced a shutdown, a series of continuing resolutions, and at times a focus on everything but the budget. Until the last couple of days, it appeared that leaders in Congress had almost no interest in finally closing the books on a budget that is now four months overdue.

Even as one obstacle got removed, it threatened to return with a vengeance — almost literally. Schumer decided to take immigration issues off the table for the moment after having been burned in the previous shutdown. But voila, the specter of a shutdown reappeared briefly on Tuesday anyway — this time from the White House. Frustrated by what he sees as Democratic unwillingness to bargain on immigration, President Trump told a White House roundtable on the Central America MS-13 organized crime gang that he's fine with another shutdown. "If we don't get rid of these loopholes where killers are allowed to come into our country," Trump vented, "we'll do a shutdown, and it's worth it for our country."

Like Schumer's Democratic caucus, however, Republicans on Capitol Hill don't seem to have the same enthusiasm for a halt to government operations. Rep. Barbara Comstock (R-Va.), one of the most endangered GOP incumbents in the 2018 midterms, told Trump, "We don't need a government shutdown on this. … I think both sides have learned that a government shutdown was bad." Rep. Peter King (R-N.Y.) told reporters that he didn't think Trump meant the threat for the near term anyway. "I don't see that at all in the offing."

Both parties have learned the hard way about government shutdowns, but have they learned enough to avoid them by passing budgets? Perhaps, but not through renewed fiscal discipline. Instead, they have decided to just spend even more money in an attempt to rope together enough votes to finish off the 2018 budget.

The main sticking point for both parties are adjustments to the caps on defense and non-defense discretionary spending, the "sequester" limits first imposed in the budget battles of 2010 and 2011. Former President Obama first suggested the idea as a means to make both sides miserable, but then-House Speaker John Boehner (R-Ohio) embraced the idea as a means to keep the federal government from expanding, a key goal for fiscal conservatives.

The caps got an adjustment in 2013's budget, but since then, the issue has ground into a stalemate. The military has chafed at its restricted funding while its missions expanded, especially in the fight against ISIS. Republicans have demanded an end to the sequester as a national-security issue, while Democrats refused to budge without a dollar-for-dollar increase in non-defense discretionary spending. And that tension has been enough to keep government growth in check, albeit in a less-than-responsible fashion at times.

Unfortunately, rather than search for a responsible and rational manner to live within its means — or at least to keep from going too much further outside its means — Congress has chosen instead to spend wildly enough for both sides to make the problem go away.

According to Politico's Burgess Everett and Sarah Ferris, the new proposal from Senate negotiators is to add $300 billion in higher spending over the next two years, split evenly between defense and non-defense discretionary spending. It will necessarily require raising the debt ceiling, both in terms of the new spending and the drop in revenue expected to come in the short term from the tax reform bill passed in December. The increase in budget caps would dwarf the expansion in the 2013 compromise ($63 billion, also over two years).

That will undoubtedly provoke the ire of fiscal conservatives in the House, but The Associated Press reports that House Speaker Paul Ryan (R-Wis.) may have outflanked them. "GOP defense hawks were prevailing over the party's depleted ranks of deficit hawks," Andrew Taylor writes, "championing major new spending on military programs." Democrats will get new spending on opioid intervention and the community health centers that they have recently touted to get their dollar-for-dollar expansion. The result, Taylor warns, "could be the return of trillion-dollar deficits for the first time since Obama's first term."

So much for Republican spending discipline, eh? And for that matter, so much for the feigned concern over deficits in the Democrats' opposition to the tax reform bill, too. When the chips are down, both parties gobble them up enthusiastically and then borrow more money for the dip. Despite having the budget caps in place for more than six years, Congress has not reconsidered the scope of America's military mission and its expense, nor the limits of federal beneficence and the emergency mindset of domestic programs long after the end of the Great Recession. And those budget issues pale in comparison to the irresponsibility of borrowing 40 percent of the money spent in the overall budget and the massive fiscal cliffs ahead in entitlement programs as the population ages.

If the Senate rolls the budget compromise into the continuing resolution passed by the House on Tuesday and forces the House to pass it, Congress can at least stop kicking the 2018 budget can down the road, but that's only a small relief. Time's running out for the other cans, whether Congress stops kicking or not.