President Donald Trump's Senate impeachment trial promises to leave him more powerful in Washington — and possibly more vulnerable to defeat on the campaign trail.

That's in part because a handful of pivotal Senate Republicans chose to criticize Trump's behavior in office while protecting him from both official sanction and the potential jeopardy of witnesses unraveling his impeachment defense under oath. As a result, Trump is on the verge of emerging from the trial with a tacit green light to defy Congress without fear of reprisal, and also safe in the knowledge that elected representatives will push only so far to find out whether he tells the truth to the public.

"It’s arguable that he’s the most politically powerful president in American history," presidential biographer Jon Meacham said on NBC News during a break in the trial Friday.

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But that power, demonstrated with the Senate's 51-49 vote Friday against considering new evidence, combined with the mild rebukes from GOP senators to dilute the most compelling aspect of his political brand. It will be harder for Trump to cast himself as a victim of the system after allies in the Senate said he overstepped the bounds of his authority and then used their power to bail him out of trouble.

The more he looks like he's rigging the system, the less it looks rigged against him.

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So there's a potential political silver lining for Democrats in their failure to win over enough Republicans to force White House officials to testify. They were quick to demonstrate how they will portray the Republican-led Senate as a tool Trump used to cover up his actions.

"How do you have a trial without witnesses?" Sen. Bernie Sanders, I-Vt., the polling leader ahead of Monday's first-in-the-nation Democratic presidential caucuses asked in a video posted online by his campaign Friday.

"This is outrageous, this is a mockery of justice and is sadly consistent with a president who believes he is above the law," Sanders said. "He is the beneficiary of a show trial that refused to allow the American people to hear the evidence against him."

In effect, the key group of GOP senators — Lamar Alexander of Tennessee, Rob Portman of Ohio and Marco Rubio of Florida among them — accepted a White House defense that held there is nothing a president can do in pursuit of his own re-election, and little he can do short of flat-out treason or taking cash bribes, that would warrant removing him from office.

But while they gave Trump nearly a blank check to wield power over Congress for at least the nearly 12 months remaining in his current term, they also handed Democrats a separate cache of political ammunition to use against him in the 2020 election. Not only will the opposition accuse Trump of benefiting from a cover-up, and Republicans lawmakers of executing it for him, but they now have a bank of statements showing some senators think what Trump did was wrong.

Portman said in a statement that Trump's "actions in this case — including asking a foreign country to investigate a potential political opponent and the delay of aid to Ukraine — were wrong and inappropriate." In doing so, he both criticized Trump and said in broad terms that the president had done what was alleged. Portman staked his decision to vote for acquittal on the very specific idea that Trump shouldn't be removed "in the middle of an election" based on the charges for which he was impeached.

Rubio tiptoed around the particulars of the allegations against Trump in a Medium post. Rubio hinted that he believed the charges rather than stating that outright, saying his decision to vote against ousting Trump was based on a logical framework that assumed the allegations were true. "Just because actions meet a standard of impeachment does not mean it is in the best interest of the country to remove a president from office," he wrote.

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Rubio said he decided Trump should not be shown the door "because doing so would inflict extraordinary and potentially irreparable damage to our already divided nation."

If the senators were trying to please all sides, it didn't work.

"This kind of thing is why voters dislike politicians so intently," said Reed Galen, a Republican strategist who sits on the advisory board of the anti-Trump super PAC The Lincoln Project. "Everyone knows they’re too chicken to do the right thing, so they say something mealy-mouthed and transparent."

What's clear from Trump's brief time in the political arena is that he will understand Congress has no appetite to stand in his way at all. Even fellow Republicans who believe he did what the House charged, and that it was wrong, aren't interested in hearing from witnesses who say he has misled the public.

At the same time, by helping him make such an ostentatious show of his power in the Senate, and by making clear they are uncomfortable with the way he used that power in the Ukraine affair, they have taken away some of his political magic — and given Democrats a better case to make to voters.