Last week, House impeachment managers wrapped up three days of statements supporting two articles of impeachment against President Trump, after which Trump’s legal team began its response. Earlier, the Senate met to receive and formally accept the articles of impeachment and adopted supplementary rules for the trial.

Here are three takeaways after the first week.

1. Republicans are not as unified as their votes suggest.

The Senate has standing impeachment trial rules — but those are silent on key procedural matters. And so, as last week’s proceedings began, senators argued over supplemental trial rules. In amending and adopting those extra rules, senators voted nearly in lockstep with their parties. Of the 11 amendments offered by Democrats, 10 were killed on a party-line vote. Only once did a Republican senator, Susan Collins of Maine, side with the Democrats — on a minor change that would have allowed more time for filing responses to motions. Senators then adopted the supplementary rules for the trial, 53 to 47, on a straight party-line vote.

But Republicans might not be as unified as those roll-call votes suggest. The final rules differed from the draft originally circulated by Senate Majority Leader Mitch McConnell (R-Ky.). The new rules added time for presentations and allowed House evidence to be automatically entered into the record. These changes reflected some GOP senators’ concerns and McConnell’s desire to keep his party conference unified. While Senate party leaders have influence, ultimately a Senate majority makes its rules.

Notably, this is the first presidential impeachment trial in which the Senate is controlled by the president’s party. McConnell and fellow GOP leaders intend to exploit their agenda-setting power to prevent the party’s divisions from being displayed. McConnell has strategically ignored Trump’s earlier demand for an immediate vote to dismiss the trial; he has also postponed any direct votes on whether the chamber will subpoena witnesses and documents, as the Democrats want, until after the opening arguments by the House managers and the president’s legal team. This has, for now, saved moderate GOP senators from a difficult vote — and saved their party from risking losing a floor vote at the trial’s start.

2. The senators aren’t just voting their consciences.

Citizens often implore legislators to “just do the right thing” — a demand lawmakers rarely heed. Political interests, more so than personal beliefs, typically shape lawmakers’ stands. Political scientists such as Richard Fenno and David Mayhew suggest three such motivations: influencing policy outcomes, getting reelected and increasing (or maintaining) power. All these were on display last week, for individual lawmakers and their parties.

When these motivations conflict, politicians and policymakers face difficult choices. Some of these are obvious. For instance, Republican senators like Collins, Cory Gardner of Colorado and Thom Tillis of North Carolina need to balance the goal of winning reelection in states where Trump is unpopular with maintaining their standing in a party in which Trump is quite popular — and could personally turn on them if they defect. These senators have chosen a variety of strategies, including vocal centrism, silence and partisanship.

Other considerations are more complex, and politicians’ goals less discernible. Because it’s unlikely that the Senate will vote to remove Trump from office, Democrats are probably eyeing other goals, such as maintaining control of the House, defeating swing-state GOP senators and hurting the president’s chances of reelection.

Even GOP senators from safe seats may be facing strategic choices. Sens. Tom Cotton of Arkansas and Josh Hawley of Missouri are commonly mentioned as possible presidential candidates. They may be weighing how their actions during this trial will be seen in an unknown GOP future, especially as Trump’s standing is weaker among younger Republican voters. Similarly, retiring senators, like Lamar Alexander of Tennessee, may be free from worries about reelection but not from issues such as how their positions during the trial will affect their future employment, legacy and conscience.

The public has been paying an unusual amount of attention to the trial, at least compared with how much people focus on normal legislative activity. That means political figures must weigh the consequences of their tactics inside and outside the Senate. This may be why the GOP hasn’t put on the wild show trial that some observers had feared or dismissed the charges altogether. Although in recent years both parties have increasingly played hardball power politics — exploiting the rules of the game for political advantage — such approaches still must be deployed judiciously for fear of too much public outrage.

House managers also toned down their rhetoric Thursday after GOP complaints and Chief Justice John G. Roberts Jr.’s admonition. That’s probably to the Democrats’ advantage. Their sharp accusations during the opening days probably would make it easier for swing-state Republicans to toe the party line — while making swing-district Democrats more vulnerable to attacks from future GOP House challengers.

3. The outcome may be almost certain, but the impact remains unknown.

The Senate is highly unlikely to remove Trump from office. But even though the arguments are unlikely to change senators’ votes, the trial still matters. Impeachment is not just about conviction or acquittal. How will the public interpret the trial?

The trial is unlikely to broadly shift public opinion. But even a marginal change in the president’s approval rating could affect control of the White House and Congress next year. Especially in a nation as deeply divided as the United States, electoral politics are fought on the margins. A handful of percentage points makes the difference between an election in which nothing changes and an election that sweeps the other party into power. The United States has never before had an impeached president running for reelection. That alone significantly raises the stakes on how the public comes to think about the trial.

Further, as political scientist Jonathan Bernstein has written, the trial — and the public’s reaction to it — will reshape what future presidents and congressional leaders think about power, possibilities and strategy. Will presidents feel emboldened to simply ignore congressional oversight? Or will they think twice before crossing Congress on appropriations, subpoenas and investigations?

We won’t know the answer to these questions until after the trial — or, really, after the election. But politicians’ choices during the trial will shape those answers.

Matt Glassman (@MattGlassman312) is a senior fellow at the Government Affairs Institute at Georgetown University.

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